REVIEW URRENT C OPINION
Nail disorders in infants and children Bianca Maria Piraccini and Michela Starace
Purpose of review Nail diseases in infants and children are an uncommon cause of consultation and are often difficult to diagnose and to manage. This review will cover nail diseases that are most commonly seen in clinical practice, including congenital and hereditary disorders and inflammatory, infective, and neoplastic nail diseases. The purpose of the review is to help the reader to recognize nail disorders at an early age and to manage them appropriately. Recent findings Two recent large studies have reported the clinical findings of genetic disorders involving the nails, that is, pachyonychia congenita and epidermolysis bullosa. Only a few articles gave a comprehensive review of a disease, as occurred for onychomycosis, while the majority of the reports published in the recent literature involve single cases. Summary Nail diseases in children and neonates are not easy to diagnose by nonexperts. Basic knowledge of the anatomy and biology of the nail facilitates their diagnosis as the understanding of their pathophysiology. This review gives hints at the most common nail diseases that affect infants and children. Keywords children, infants, melanocyte nevi, nail disorders, onychomycosis
INTRODUCTION Nail disorders in infants and children are an uncommon cause of dermatological visit. They may be congenital and hereditary or may be acquired. In the first two cases, nail signs are present at birth or develop during neonatal life and may occasionally be a sign of a syndrome or a systemic disorder [1,2]. Acquired nail conditions occurring in children are usually the same as seen in adults, but their frequency is different, and may depend on the age observed. For example, common diseases typically seen in adults, such as onychomycosis or tumors, rarely occur in children. On the other hand, some inflammatory nail disorders, such as parakeratosis pustulosa and nail lichen striatus, are typical of the child. This article reviews nail disorders that are most commonly observed in infants and children, starting from basic details of anatomy and biology of the nail, in order to explain development and morphology of the nail symptoms.
ANATOMY AND BIOLOGY OF NAIL UNIT The nail unit is formed by four specialized epithelia: the nail matrix, the nail bed, the proximal nail fold, and the hyponychium [3,4 ]. The nail matrix, a &&
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germinative epithelium, is responsible for the production of the nail plate and consists of a proximal and a distal region. Proliferation and keratinization of nail matrix cells occur along an oblique axis. As a consequence, the proximal part of nail matrix produces the dorsal portion of the nail plate and, when damaged, gives rise to the development of nail plate surface abnormalities, whereas the distal part of nail matrix produces the ventral portion of the nail plate. The only part of the nail matrix visible from the outside is the lunula, a proximal whitish, opaque, half-moon-shaped area, with distal convexity, best seen in the fingernails. It corresponds to the distal nail matrix. The nail plate is a hard and elastic structure that is produced continuously by the nail matrix; it is transparent and appears pink for the presence of the vessels of the underlying nail bed. The nail plate is firmly attached to the nail bed and it detaches at the Division of Dermatology, Department of Experimental, Diagnostic and Specialty Medicine, University of Bologna, Bologna, Italy Correspondence to Bianca Maria Piraccini, Division of Dermatology, Department of Experimental, Diagnostic and Specialty Medicine, Via Massarenti, 1, Bologna 40138, Italy. Tel.: +39 0516363677; fax: +39 0516364867; e-mail: [email protected]. Curr Opin Pediatr 2014, 26:440–445 DOI:10.1097/MOP.0000000000000116 Volume 26 Number 4 August 2014
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Nail disorders in infants and children Piraccini and Starace
KEY POINTS Significant knowledge of nail anatomy and physiology is the best way to approach nail diseases. Nail diseases in infants and children are uncommon. An acquired nail dystrophy in children is usually due to an inflammatory or infective disease, as nail tumors are rare. Treatment of nail disorders in children should consider age and severity of the condition.
hyponychium, where its color becomes white due to the presence of air underneath. The nail bed is responsible for the adhesion of the plate during the growth of the nail; it is richly vascularized by capillaries oriented longitudinally in parallel ridges. Proximally and laterally, the nail plate is surrounded by the nail folds that are responsible for the protection of the nail matrix. The growth of the nail plate is continuous during life. The speed of growth increases with age until the age of 10–14 years, when it becomes similar to that of adults (15 mm/day). At birth, the nails of newborns are thin, soft, and completely formed and their size is related to gestational age and weight of the newborn. There are two physiological aspect of the nail of the newborn that are exclusive to this age: the presence of a certain degree of koilonychia, especially in the toenails, and a transient light-brown or ochre pigmentation of the proximal nail fold [5].
CONGENITAL AND HEREDITARY NAIL DISEASES Congenital and hereditary nail diseases are a group of conditions in which nail abnormalities are present at birth or appear during the first years of life.
Congenital malalignment of the big toenail Congenital malalignment of the big toenail is a lateral deviation of the nail plate from the longitudinal axis of the distal phalanx that is not parallel to the distal phalanx of the digit. It is an isolated nail condition, probably caused by an abnormality in the ligament that connects the nail matrix to the periosteum of the distal phalanx or due to an excessive traction by a hypertrophic extensor tendon of the hallux [6]. The condition is often bilateral and may be complicated by the development of lateral or distal nail embedding, which is more frequent when hypertrophy of the lateral nail fold is associated [7]. The affected nail may be thickened, with a triangular shape and surface changes due to repetitive traumas (Fig. 1).
FIGURE 1. Congenital malalignment of the great toenails: the longitudinal axes of the nails do not parallel those of the digits. The nail plates are thickened and show several Beau’s lines.
Spontaneous improvement of nail plate deviation is reported in up to 50%. Surgical treatment is recommended for severe cases that do not tend to improve spontaneously. It is performed at the age of 2–5 years, with the so-called ‘ungueodermal flap’, which allows repositioning of the entire nail apparatus in the normal orientation [8].
Nail–patella syndrome This condition is due to a mutation of the gene LMX1B localized on chromosome 9q34.1 [9,10] and is inherited in an autosomal dominant pattern with variable expressivity. Nail hypoplasia is associated with bone and kidney abnormalities. Nail changes may be limited to the fingernails, usually the thumbs, with hypoplasia or absence of the nail plate. Triangular lunulae are also characteristic. Bone abnormalities include absent or hypoplastic patella, radial head abnormalities, and iliac crest exostosis. A pelvis X-ray permits diagnosis of nail– patella syndrome in children. Prompt diagnosis may help to prevent severe kidney damage.
Epidermolysis bullosa Epidermolysis bullosa includes a group of inherited blistering skin diseases, distinguished into three different types: epidermic, junction, and dystrophic. The dominant epidermolysis bullosa starts at birth while recessive epidermolysis bullosa appears between the ages of 5 and 8 years. Nail abnormalities are not specific for a particular epidermolysis bullosa, as they result from blistering and scarring of nail matrix and nail bed, favored by trauma. The most common signs include nail blisters, erosions, anonychia, nail atrophy, onychogryphosis, nail thickening, and parrot beak nail deformity [11]. In advanced stages, repetitive blistering may produce permanent nail loss.
Pachyonychia congenita Pachyonychia congenita is an autosomal dominant inherited condition due to mutations of four keratin
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genes (KRT6A, 6B, 16, 17), characterized by early development of nail thickening with an increased curvature due to nail bed hyperkeratosis, associated with palmoplantar keratoderma. Nail and skin changes are present at birth in only 50% of the cases, but, by 5 years of age, they are seen in more than 75% of the children [12]. By the age of 10 years, pain is a commonly associated symptom and greatly impairs quality of life. Toenail thickening is the most common finding, with severe subungual keratosis and difficulty in trimming nails (Fig. 2). A review of the clinical findings of pachyonychia congenita in a large series of patients, with genetically confirmed pachyonychia congenita, suggested that the most suggestive symptoms for pachyonychia congenita are toenail dystrophy associated with plantar keratoderma and plantar pain in children older than 3 years [13 ]. &
ACQUIRED NAIL DISEASES They are the most common types of onychodystrophies and are typically seen in children above the age of 4 years.
Parakeratosis pustulosa Parakeratosis pustulosa is uncommon and exclusively seen in children, usually between the ages of 5 and 7 years. It usually involves a single digit of the hand, often the thumb or index finger, and presents with mild eczematous changes of the pulp associated with psoriasiform nail changes (mild subungual hyperkeratosis and onycholysis) (Fig. 3) [14]. Pitting of the nail plate may be present. Parakeratosis pustulosa can be considered a mild form of psoriasis, as some of the affected children develop nail psoriasis in adults. The nail lesions usually regress spontaneously; skin eczema may improve with the topical application of low-potency steroids and/or vitamin D derivatives.
Psoriasis Nail psoriasis is more rare in children than in adults, occurring in 10–40% of the children with skin lesions. It can also be limited to the nails. The clinical manifestations are similar to those of adults, but in children they are usually mild and frequently go unnoticed by the child and the parents [15 ]. Fingernail pitting and toenail thickening with subungual hyperkeratosis, due to accumulation of scales under the nail plate, are the most common signs of psoriasis in children. Psoriatic pits are usually large, deep, and irregular. Toenail thickening may involve one, several, or all toenails and may result from nail plate thickening due to matrix psoriasis or nail bed hyperkeratosis [15 ]. Differential diagnosis with onychomycosis may require mycology. Treatment of children with nail psoriasis includes urea-containing creams or lacquers, to reduce toenail thickening, and topical combinations &&
INFLAMMATORY NAIL DISEASES They include disorders typical of childhood, such as parakeratosis pustolosa and nail lichen striatus, and disorders seen in both children and adults, such as psoriasis and lichen planus.
&&
FIGURE 2. Pachyonychia congenita: the fingernails and the toenails are thickened. 442
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FIGURE 3. Parakeratosis pustulosa: the third finger shows eczema of the periungual tissues with mild onycholysis. Volume 26 Number 4 August 2014
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Nail disorders in infants and children Piraccini and Starace
of steroids and calcipotriene when the disease involves the nail bed.
Twenty-nail dystrophy (trachyonychia) Trachyonychia (TND), or twenty-nail dystrophy, is a benign inflammatory nail disease commonly observed in children. In some cases, it is associated with severe alopecia areata, while in other children it is an isolated skin finding (idiopathic TND). TND is not a distinctive disease but is only the clinical result of disorders that involve the nail matrix, including alopecia areata, lichen planus, eczema, and psoriasis [16]. TND is characterized by nail plate surface abnormalities appearing as nail roughness, resulting from a mild inflammation of the proximal nail matrix. One, several, or all nails may be affected, with diffuse roughness resulting from thin and regular longitudinal fissures. The nail plate is usually opaque and may be thinned with koilonychia. Cuticle hyperkeratosis is another possible finding (Fig. 4). The disorder is symptomless and usually regresses spontaneously with aging. Severe nail roughness may benefit from application of ureacontaining emollients.
Lichen striatus Nail lichen striatus is rare and almost exclusively seen in children. One digit, usually a finger, shows lichenoid nail abnormalities, that is, longitudinal fissuring, thinning, and distal nail splitting, restricted to its medial or lateral portion (Fig. 5). Nail changes may be isolated or associated with typical skin lesions, with papules or verrucous lesions in a linear distribution. The condition regresses spontaneously in a few years, although some cases with
FIGURE 5. Lichen striatus of the nail: lichenoid changes, that is, nail thinning, longitudinal fissures, and distal splitting, confined to one side of one nail in a child.
long-lasting course have recently been reported [17]. Cutaneous changes may benefit from topical therapy with tacrolimus or combining a retinoid with a steroid [18].
Lichen planus Nail involvement by lichen planus is less common in children than in adults, occurring in about 14– 20% of the cases [19]. As in adults, lichen planus may be limited to the nails even in children. Nail lesions are usually mild, with several nails showing thinning and longitudinal fissures with distal nail splitting. Nail bed involvement with mild onycholysis and subungual hyperkeratosis is another possible presentation. These cases require a longitudinal nail biopsy to confirm the diagnosis. Although nail pterygium is an uncommon outcome, systemic therapy with steroids for 3–5 months is advisable.
INFECTIONS They are a very common cause of nail dystrophies in school-aged children and include viral, bacterial, and mycotic infections.
Warts
FIGURE 4. Trachyonychia: nail plate is opaque and thin, with longitudinal striations. The cuticles are hyperkeratotic.
Human papilloma virus-induced warts are very common in children above 6 years of age, especially in the fingernails, where they are often spread from nail to nail by nail biting. The wart may be periungual, appearing as a hyperkeratotic lesion of the nail fold, or subungual, presenting as a hyperkeratotic mass associated with distal onycholysis. Dermoscopy can be very useful for diagnosis of very small warts, as it shows the irregular surface with pointed hemorrhages [20]. Although spontaneous regression of warts is reported to occur in about 30% of the cases,
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treatment is advisable when the lesion causes pain and to avoid its spreading. Topical application of keratolytic solutions containing salicylic acid and urea is the first-choice therapy in children. Other possible options, suggested in children above 12 years, include topical immunotherapy (for multiple and recalcitrant warts) [21] and pulsed dye laser.
Acute paronychia Acute paronychia is an inflammation of the nail fold that follows a trauma with penetration of pathogens into the skin. It is very common in children’s fingernails, since the habit of biting the cuticle and finger sucking induces trauma and maceration of periungual skin. The commonest pathogen is Staphylococcus aureus, but other bacteria and herpes simplex virus may be responsible. The affected digit shows erythema and swelling, more marked on one side, associated with pain. Abscess formation is uncommon in at a young age. Acute paronychia is not usually referred to the doctor, as its short course does not induce worry. Dermatological consultation is, on the other hand, frequently asked for the outcomes of the acute episode. When the inflammation is severe, it may, in fact, cause transitory or permanent matrix damage, appearing as onychomadesis or nail plate dystrophy. Cytological examination with Tzanck smear permits diagnosis of the causative agent and avoids unnecessary use of antibiotics [22]. If an abscess is present, surgical drainage is necessary [23 ]. &&
Onychomycosis Onychomycosis in children is rare, with an overall prevalence below 0.5%. Dermatophytes are responsible for the great majority of cases, and predisposing factors include tinea pedis and family members affected by onychomycosis or tinea pedis. Candida sp. may rarely invade the nails, both fingernails and toenails, in predisposed children, as it occurs in premature newborns and in children with iatrogenic or genetic immunodeficiencies. Distal and lateral subungual onychomycosis is the most common clinical presentation of onychomycosis due to dermatophytes in children [24 ]. Superficial onychomycosis, in both its ‘deep’ and ‘classic’ varieties, is rare and is especially found in young children. Onychomycosis due to Candida may present as distolateral subungual onychomycosis, usually affecting fingernails and toenails, and as superficial onychomycosis. Paronychia is frequently associated. Mycology is always mandatory to confirm the diagnosis. Topical therapy, associated or not with mechanical or chemical avulsion of the affected nail, is suggested in mild distal subungual onychomycosis
of one digit and in superficial onychomycosis. Distal subungual onychomycosis due to dermatophytes involving several digits is an indication for systemic treatment, with terbinafine being the drug of choice. Dosages are one-fourth of a 250 mg tablet in children weighing less than 20 kg and half a tablet in children weighing 20–40 kg.
TUMORS Malignant as well as benign tumors of the nail are exceedingly rare in children. The most frequent benign tumors are nail matrix melanocyte nevi and exostoses.
Nail matrix nevi They are due to the presence of an increased number of pigment-producing melanocytes in the nail matrix, giving rise to the appearance of a pigmented longitudinal band in the nail plate (Fig. 6). Nail matrix nevi may be present at birth or may develop at 2–4 years of age. They involve one digit, usually a fingernail. The width of the band of melanonychia may vary from a few millimeters to the whole nail plate, and the color may be homogeneous or not and more or less dark. Pigmentation of the periungual skin (pseudo-Hutchinson’s sign) is often present. It is typical of nail matrix nevi to change color and width in time, due to variation of pigment production by the nevus melanocytes [25,26]. Management of melanonychia in children is not easy [27]. Based on our experience, we follow our children periodically and decide after puberty whether to make a tangential biopsy or not. The decision to make a biopsy in a younger child with melanonychia is taken when the parents are very anxious or
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FIGURE 6. Nail matrix nevus: brown-to-black band of longitudinal melanonychia involving a large width of the nail plate. Volume 26 Number 4 August 2014
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Nail disorders in infants and children Piraccini and Starace
when the band quickly becomes darker and invades the whole nail [28].
Exostoses Exostoses are benign tumors of the bone of the distal phalanx. They are common in adolescents and young adults, especially in the big toe, and are favored by trauma. Clinically, exostosis appears as a subungual hard nodule with a keratotic surface. The lesion may be painful and can ulcerate. The diagnosis is confirmed by X-ray examination. Treatment is surgical, the best approach being complete marginal excision through a fish mouth. This technique has only 4% of recurrences and good postoperative result [29 ]. &
CONCLUSION Although rare, nail diseases in children are a source of anxiety for the patients and should be recognized and treated, if possible. Acquired nail dystrophies are typical of the age of 5–10 years and are, commonly, due to psoriasis or infective conditions. Nail tumors are rare. Acknowledgements None. Conflicts of interest There are no conflicts of interest.
REFERENCES AND RECOMMENDED READING Papers of particular interest, published within the period of review, have been highlighted as: & of special interest && of outstanding interest 1. Shah KN, Rubin AI. Nail disorders as signs of pediatric systemic disease. Curr Probl Pediatr Adolesc Health Care 2012; 42:204–211. 2. Gupta AK, Tosti A. Nails and the clinician. Clin Dermatol 2013; 31:507–508. 3. Zaias N. The nail in health and disease. 2nd ed. Norwalk, CT: Appleton and Lange 1990. 4. de Berker D. Nail anatomy. Clin Dermatol 2013; 31:509–515. A recent overview on nail anatomy with an excellent explanation of physiology && that allows an easy understanding of nail diseases. 5. Iorizzo M, Oranje AP, Tosti A. Periungual hyperpigmentation in newborns. Pediatr Dermatol 2008; 25:25–27.
6. Wagner G, Sachse MM. Congenital malalignment of the big toe nail. J Dtsch Dermatol Ges 2012; 10:326–330. 7. Piraccini BM, Parente GL, Varotti E, et al. Congenital hypertrophy of the lateral nail folds of the hallux: clinical features and follow-up of seven cases. Pediatr Dermatol 2000; 17:348–351. 8. Jellinek NJ. Flaps in nail surgery. Dermatol Ther 2012; 25:535–544. 9. McIntosh I, Dreyer SD, Clough MV, et al. Mutation analysis of LMX1B gene in nail patella syndrome patients. Am J Hum Genet 1998; 63:1651–1658. 10. Bongers EM, Gubler MC, Knoers NV. Nail-patella syndrome: overview on clinical and molecular findings. Pediatr Nephrol 2002; 17:703–712. 11. Tosti A, de Farias DC, Murrell DF. Nail involvement in epidermolysis bullosa. Dermatol Clin 2010; 28:153–157. 12. Shah S, Boen M, Kenner-Bell B, et al. Pachyonychia congenita in pediatric patients: natural history, features, and impact. JAMA Dermatol 2014; 150: 146–153. 13. Eliason MJ, Leachman SA, Feng BJ, et al. A review of the clinical & phenotype of 254 patients with genetically confirmed pachyonychia congenita. J Am Acad Dermatol 2012; 67:680–686. A complete review of symptoms, diagnostic clues and details on quality of life of children with this disease. 14. Tosti A, Peluso AM, Zucchelli V. Clinical features and long term follow-up of 20 cases of parakeratosis pustulosa. Pediatr Dermatol 1998; 15:259–263. 15. Piraccini BM, Starace M. Nail psoriasis in special populations, children, && pregnant, elderly. In: Rigopoulos D, Tosti A. editors. Nail psoriasis: from A to Z. New York, NY: Springer; 2014 (in press). This recent work offers a good overview of clinical signs of nail psoriasis in extreme age populations. 16. Gordon KA, Vega JM, Tosti A. Trachyonychia: a comprehensive review. Indian J Dermatol Venereol Leprol 2011; 77:640–645. 17. Feely MA, Silverberg NB. Two cases of lichen striatus with prolonged active phase. Pediatr Dermatol 2014; 31:e67–68. 18. Youssef SM, Teng JM. Effective topical combination therapy for treatment of lichen striatus in children: a case series and review. J Drugs Dermatol 2012; 11:872–875. 19. Pandhi D, Singal A, Bhattacharya SN. Lichen planus in childhood: a series of 316 patients. Pediatr Dermatol 2014; 31:59–67. 20. Piraccini BM, Bruni F, Starace M. Dermoscopy of nonskin cancer nail disorders. Dermatol Ther 2012; 25:594–602. 21. Choi Y, Kim do H, Jin SY, et al. Topical immunotherapy with diphenylcyclopropenone is effective and preferred in the treatment of periungual warts. Ann Dermatol 2013; 25:434–439. 22. Durdu M, Ruocco V. Clinical and cytologic features of antibiotic-resistant acute paronychia. J Am Acad Dermatol 2014; 70:120–126. 23. Haneke E. Nail surgery. Clin Dermatol 2013; 31:516–525. This recent review on nail surgery moves step by step from the basic to the && more difficult surgery, giving helpful hints for the best result. 24. Piraccini BM, Bruni F, Starace M. Onychomycosis in children. Expert Rev Dermatol 2012; 7:558–569. & This recent review on onychomycosis in children covers epidemiology, clinical features, predisposing factors and management of this rare and overdiagnosed disease. 25. Tosti A, Baran R, Piraccini BM, et al. Nail matrix nevi: a clinical and histopathologic study of twenty-two patients. J Am Acad Dermatol 1996; 34(5 Pt 1):765–771. 26. Goettmann-Bonvallot S, Andre` J, Belaich S. Longitudinal melanonychia in children: a clinical and histopathologic study of 40 cases. J Am Acad Dermatol 1999; 41:17–22. 27. Tosti A, Piraccini BM, de Farias DC. Dealing with melanonychia. Semin Cutan Med Surg 2009; 28:49–54. 28. Tosti A, Piraccini BM, Cagalli A, et al. In situ melanoma of the nail unit in children: report of two cases in fair-skinned Caucasian children. Pediatr Dermatol 2012; 29:79–83. 29. DaCambra MP, Gupta SK, Ferri-de-Barros F. Subungual exostosis of the toes: a systemic review. Clin Orthop Relat Res 2014; 472: 1251–1259. & A systematic review of subungual exostosis, giving a guide to the best management.
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Nail disorders in infants and children Bianca Maria Piraccini and Michela Starace
Purpose of review Nail diseases in infants and children are an uncommon cause of consultation and are often difficult to diagnose and to manage. This review will cover nail diseases that are most commonly seen in clinical practice, including congenital and hereditary disorders and inflammatory, infective, and neoplastic nail diseases. The purpose of the review is to help the reader to recognize nail disorders at an early age and to manage them appropriately. Recent findings Two recent large studies have reported the clinical findings of genetic disorders involving the nails, that is, pachyonychia congenita and epidermolysis bullosa. Only a few articles gave a comprehensive review of a disease, as occurred for onychomycosis, while the majority of the reports published in the recent literature involve single cases. Summary Nail diseases in children and neonates are not easy to diagnose by nonexperts. Basic knowledge of the anatomy and biology of the nail facilitates their diagnosis as the understanding of their pathophysiology. This review gives hints at the most common nail diseases that affect infants and children. Keywords children, infants, melanocyte nevi, nail disorders, onychomycosis
INTRODUCTION Nail disorders in infants and children are an uncommon cause of dermatological visit. They may be congenital and hereditary or may be acquired. In the first two cases, nail signs are present at birth or develop during neonatal life and may occasionally be a sign of a syndrome or a systemic disorder [1,2]. Acquired nail conditions occurring in children are usually the same as seen in adults, but their frequency is different, and may depend on the age observed. For example, common diseases typically seen in adults, such as onychomycosis or tumors, rarely occur in children. On the other hand, some inflammatory nail disorders, such as parakeratosis pustulosa and nail lichen striatus, are typical of the child. This article reviews nail disorders that are most commonly observed in infants and children, starting from basic details of anatomy and biology of the nail, in order to explain development and morphology of the nail symptoms.
ANATOMY AND BIOLOGY OF NAIL UNIT The nail unit is formed by four specialized epithelia: the nail matrix, the nail bed, the proximal nail fold, and the hyponychium [3,4 ]. The nail matrix, a &&
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germinative epithelium, is responsible for the production of the nail plate and consists of a proximal and a distal region. Proliferation and keratinization of nail matrix cells occur along an oblique axis. As a consequence, the proximal part of nail matrix produces the dorsal portion of the nail plate and, when damaged, gives rise to the development of nail plate surface abnormalities, whereas the distal part of nail matrix produces the ventral portion of the nail plate. The only part of the nail matrix visible from the outside is the lunula, a proximal whitish, opaque, half-moon-shaped area, with distal convexity, best seen in the fingernails. It corresponds to the distal nail matrix. The nail plate is a hard and elastic structure that is produced continuously by the nail matrix; it is transparent and appears pink for the presence of the vessels of the underlying nail bed. The nail plate is firmly attached to the nail bed and it detaches at the Division of Dermatology, Department of Experimental, Diagnostic and Specialty Medicine, University of Bologna, Bologna, Italy Correspondence to Bianca Maria Piraccini, Division of Dermatology, Department of Experimental, Diagnostic and Specialty Medicine, Via Massarenti, 1, Bologna 40138, Italy. Tel.: +39 0516363677; fax: +39 0516364867; e-mail: [email protected]. Curr Opin Pediatr 2014, 26:440–445 DOI:10.1097/MOP.0000000000000116 Volume 26 Number 4 August 2014
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Nail disorders in infants and children Piraccini and Starace
KEY POINTS Significant knowledge of nail anatomy and physiology is the best way to approach nail diseases. Nail diseases in infants and children are uncommon. An acquired nail dystrophy in children is usually due to an inflammatory or infective disease, as nail tumors are rare. Treatment of nail disorders in children should consider age and severity of the condition.
hyponychium, where its color becomes white due to the presence of air underneath. The nail bed is responsible for the adhesion of the plate during the growth of the nail; it is richly vascularized by capillaries oriented longitudinally in parallel ridges. Proximally and laterally, the nail plate is surrounded by the nail folds that are responsible for the protection of the nail matrix. The growth of the nail plate is continuous during life. The speed of growth increases with age until the age of 10–14 years, when it becomes similar to that of adults (15 mm/day). At birth, the nails of newborns are thin, soft, and completely formed and their size is related to gestational age and weight of the newborn. There are two physiological aspect of the nail of the newborn that are exclusive to this age: the presence of a certain degree of koilonychia, especially in the toenails, and a transient light-brown or ochre pigmentation of the proximal nail fold [5].
CONGENITAL AND HEREDITARY NAIL DISEASES Congenital and hereditary nail diseases are a group of conditions in which nail abnormalities are present at birth or appear during the first years of life.
Congenital malalignment of the big toenail Congenital malalignment of the big toenail is a lateral deviation of the nail plate from the longitudinal axis of the distal phalanx that is not parallel to the distal phalanx of the digit. It is an isolated nail condition, probably caused by an abnormality in the ligament that connects the nail matrix to the periosteum of the distal phalanx or due to an excessive traction by a hypertrophic extensor tendon of the hallux [6]. The condition is often bilateral and may be complicated by the development of lateral or distal nail embedding, which is more frequent when hypertrophy of the lateral nail fold is associated [7]. The affected nail may be thickened, with a triangular shape and surface changes due to repetitive traumas (Fig. 1).
FIGURE 1. Congenital malalignment of the great toenails: the longitudinal axes of the nails do not parallel those of the digits. The nail plates are thickened and show several Beau’s lines.
Spontaneous improvement of nail plate deviation is reported in up to 50%. Surgical treatment is recommended for severe cases that do not tend to improve spontaneously. It is performed at the age of 2–5 years, with the so-called ‘ungueodermal flap’, which allows repositioning of the entire nail apparatus in the normal orientation [8].
Nail–patella syndrome This condition is due to a mutation of the gene LMX1B localized on chromosome 9q34.1 [9,10] and is inherited in an autosomal dominant pattern with variable expressivity. Nail hypoplasia is associated with bone and kidney abnormalities. Nail changes may be limited to the fingernails, usually the thumbs, with hypoplasia or absence of the nail plate. Triangular lunulae are also characteristic. Bone abnormalities include absent or hypoplastic patella, radial head abnormalities, and iliac crest exostosis. A pelvis X-ray permits diagnosis of nail– patella syndrome in children. Prompt diagnosis may help to prevent severe kidney damage.
Epidermolysis bullosa Epidermolysis bullosa includes a group of inherited blistering skin diseases, distinguished into three different types: epidermic, junction, and dystrophic. The dominant epidermolysis bullosa starts at birth while recessive epidermolysis bullosa appears between the ages of 5 and 8 years. Nail abnormalities are not specific for a particular epidermolysis bullosa, as they result from blistering and scarring of nail matrix and nail bed, favored by trauma. The most common signs include nail blisters, erosions, anonychia, nail atrophy, onychogryphosis, nail thickening, and parrot beak nail deformity [11]. In advanced stages, repetitive blistering may produce permanent nail loss.
Pachyonychia congenita Pachyonychia congenita is an autosomal dominant inherited condition due to mutations of four keratin
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genes (KRT6A, 6B, 16, 17), characterized by early development of nail thickening with an increased curvature due to nail bed hyperkeratosis, associated with palmoplantar keratoderma. Nail and skin changes are present at birth in only 50% of the cases, but, by 5 years of age, they are seen in more than 75% of the children [12]. By the age of 10 years, pain is a commonly associated symptom and greatly impairs quality of life. Toenail thickening is the most common finding, with severe subungual keratosis and difficulty in trimming nails (Fig. 2). A review of the clinical findings of pachyonychia congenita in a large series of patients, with genetically confirmed pachyonychia congenita, suggested that the most suggestive symptoms for pachyonychia congenita are toenail dystrophy associated with plantar keratoderma and plantar pain in children older than 3 years [13 ]. &
ACQUIRED NAIL DISEASES They are the most common types of onychodystrophies and are typically seen in children above the age of 4 years.
Parakeratosis pustulosa Parakeratosis pustulosa is uncommon and exclusively seen in children, usually between the ages of 5 and 7 years. It usually involves a single digit of the hand, often the thumb or index finger, and presents with mild eczematous changes of the pulp associated with psoriasiform nail changes (mild subungual hyperkeratosis and onycholysis) (Fig. 3) [14]. Pitting of the nail plate may be present. Parakeratosis pustulosa can be considered a mild form of psoriasis, as some of the affected children develop nail psoriasis in adults. The nail lesions usually regress spontaneously; skin eczema may improve with the topical application of low-potency steroids and/or vitamin D derivatives.
Psoriasis Nail psoriasis is more rare in children than in adults, occurring in 10–40% of the children with skin lesions. It can also be limited to the nails. The clinical manifestations are similar to those of adults, but in children they are usually mild and frequently go unnoticed by the child and the parents [15 ]. Fingernail pitting and toenail thickening with subungual hyperkeratosis, due to accumulation of scales under the nail plate, are the most common signs of psoriasis in children. Psoriatic pits are usually large, deep, and irregular. Toenail thickening may involve one, several, or all toenails and may result from nail plate thickening due to matrix psoriasis or nail bed hyperkeratosis [15 ]. Differential diagnosis with onychomycosis may require mycology. Treatment of children with nail psoriasis includes urea-containing creams or lacquers, to reduce toenail thickening, and topical combinations &&
INFLAMMATORY NAIL DISEASES They include disorders typical of childhood, such as parakeratosis pustolosa and nail lichen striatus, and disorders seen in both children and adults, such as psoriasis and lichen planus.
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FIGURE 2. Pachyonychia congenita: the fingernails and the toenails are thickened. 442
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FIGURE 3. Parakeratosis pustulosa: the third finger shows eczema of the periungual tissues with mild onycholysis. Volume 26 Number 4 August 2014
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Nail disorders in infants and children Piraccini and Starace
of steroids and calcipotriene when the disease involves the nail bed.
Twenty-nail dystrophy (trachyonychia) Trachyonychia (TND), or twenty-nail dystrophy, is a benign inflammatory nail disease commonly observed in children. In some cases, it is associated with severe alopecia areata, while in other children it is an isolated skin finding (idiopathic TND). TND is not a distinctive disease but is only the clinical result of disorders that involve the nail matrix, including alopecia areata, lichen planus, eczema, and psoriasis [16]. TND is characterized by nail plate surface abnormalities appearing as nail roughness, resulting from a mild inflammation of the proximal nail matrix. One, several, or all nails may be affected, with diffuse roughness resulting from thin and regular longitudinal fissures. The nail plate is usually opaque and may be thinned with koilonychia. Cuticle hyperkeratosis is another possible finding (Fig. 4). The disorder is symptomless and usually regresses spontaneously with aging. Severe nail roughness may benefit from application of ureacontaining emollients.
Lichen striatus Nail lichen striatus is rare and almost exclusively seen in children. One digit, usually a finger, shows lichenoid nail abnormalities, that is, longitudinal fissuring, thinning, and distal nail splitting, restricted to its medial or lateral portion (Fig. 5). Nail changes may be isolated or associated with typical skin lesions, with papules or verrucous lesions in a linear distribution. The condition regresses spontaneously in a few years, although some cases with
FIGURE 5. Lichen striatus of the nail: lichenoid changes, that is, nail thinning, longitudinal fissures, and distal splitting, confined to one side of one nail in a child.
long-lasting course have recently been reported [17]. Cutaneous changes may benefit from topical therapy with tacrolimus or combining a retinoid with a steroid [18].
Lichen planus Nail involvement by lichen planus is less common in children than in adults, occurring in about 14– 20% of the cases [19]. As in adults, lichen planus may be limited to the nails even in children. Nail lesions are usually mild, with several nails showing thinning and longitudinal fissures with distal nail splitting. Nail bed involvement with mild onycholysis and subungual hyperkeratosis is another possible presentation. These cases require a longitudinal nail biopsy to confirm the diagnosis. Although nail pterygium is an uncommon outcome, systemic therapy with steroids for 3–5 months is advisable.
INFECTIONS They are a very common cause of nail dystrophies in school-aged children and include viral, bacterial, and mycotic infections.
Warts
FIGURE 4. Trachyonychia: nail plate is opaque and thin, with longitudinal striations. The cuticles are hyperkeratotic.
Human papilloma virus-induced warts are very common in children above 6 years of age, especially in the fingernails, where they are often spread from nail to nail by nail biting. The wart may be periungual, appearing as a hyperkeratotic lesion of the nail fold, or subungual, presenting as a hyperkeratotic mass associated with distal onycholysis. Dermoscopy can be very useful for diagnosis of very small warts, as it shows the irregular surface with pointed hemorrhages [20]. Although spontaneous regression of warts is reported to occur in about 30% of the cases,
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Dermatology
treatment is advisable when the lesion causes pain and to avoid its spreading. Topical application of keratolytic solutions containing salicylic acid and urea is the first-choice therapy in children. Other possible options, suggested in children above 12 years, include topical immunotherapy (for multiple and recalcitrant warts) [21] and pulsed dye laser.
Acute paronychia Acute paronychia is an inflammation of the nail fold that follows a trauma with penetration of pathogens into the skin. It is very common in children’s fingernails, since the habit of biting the cuticle and finger sucking induces trauma and maceration of periungual skin. The commonest pathogen is Staphylococcus aureus, but other bacteria and herpes simplex virus may be responsible. The affected digit shows erythema and swelling, more marked on one side, associated with pain. Abscess formation is uncommon in at a young age. Acute paronychia is not usually referred to the doctor, as its short course does not induce worry. Dermatological consultation is, on the other hand, frequently asked for the outcomes of the acute episode. When the inflammation is severe, it may, in fact, cause transitory or permanent matrix damage, appearing as onychomadesis or nail plate dystrophy. Cytological examination with Tzanck smear permits diagnosis of the causative agent and avoids unnecessary use of antibiotics [22]. If an abscess is present, surgical drainage is necessary [23 ]. &&
Onychomycosis Onychomycosis in children is rare, with an overall prevalence below 0.5%. Dermatophytes are responsible for the great majority of cases, and predisposing factors include tinea pedis and family members affected by onychomycosis or tinea pedis. Candida sp. may rarely invade the nails, both fingernails and toenails, in predisposed children, as it occurs in premature newborns and in children with iatrogenic or genetic immunodeficiencies. Distal and lateral subungual onychomycosis is the most common clinical presentation of onychomycosis due to dermatophytes in children [24 ]. Superficial onychomycosis, in both its ‘deep’ and ‘classic’ varieties, is rare and is especially found in young children. Onychomycosis due to Candida may present as distolateral subungual onychomycosis, usually affecting fingernails and toenails, and as superficial onychomycosis. Paronychia is frequently associated. Mycology is always mandatory to confirm the diagnosis. Topical therapy, associated or not with mechanical or chemical avulsion of the affected nail, is suggested in mild distal subungual onychomycosis
of one digit and in superficial onychomycosis. Distal subungual onychomycosis due to dermatophytes involving several digits is an indication for systemic treatment, with terbinafine being the drug of choice. Dosages are one-fourth of a 250 mg tablet in children weighing less than 20 kg and half a tablet in children weighing 20–40 kg.
TUMORS Malignant as well as benign tumors of the nail are exceedingly rare in children. The most frequent benign tumors are nail matrix melanocyte nevi and exostoses.
Nail matrix nevi They are due to the presence of an increased number of pigment-producing melanocytes in the nail matrix, giving rise to the appearance of a pigmented longitudinal band in the nail plate (Fig. 6). Nail matrix nevi may be present at birth or may develop at 2–4 years of age. They involve one digit, usually a fingernail. The width of the band of melanonychia may vary from a few millimeters to the whole nail plate, and the color may be homogeneous or not and more or less dark. Pigmentation of the periungual skin (pseudo-Hutchinson’s sign) is often present. It is typical of nail matrix nevi to change color and width in time, due to variation of pigment production by the nevus melanocytes [25,26]. Management of melanonychia in children is not easy [27]. Based on our experience, we follow our children periodically and decide after puberty whether to make a tangential biopsy or not. The decision to make a biopsy in a younger child with melanonychia is taken when the parents are very anxious or
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FIGURE 6. Nail matrix nevus: brown-to-black band of longitudinal melanonychia involving a large width of the nail plate. Volume 26 Number 4 August 2014
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Nail disorders in infants and children Piraccini and Starace
when the band quickly becomes darker and invades the whole nail [28].
Exostoses Exostoses are benign tumors of the bone of the distal phalanx. They are common in adolescents and young adults, especially in the big toe, and are favored by trauma. Clinically, exostosis appears as a subungual hard nodule with a keratotic surface. The lesion may be painful and can ulcerate. The diagnosis is confirmed by X-ray examination. Treatment is surgical, the best approach being complete marginal excision through a fish mouth. This technique has only 4% of recurrences and good postoperative result [29 ]. &
CONCLUSION Although rare, nail diseases in children are a source of anxiety for the patients and should be recognized and treated, if possible. Acquired nail dystrophies are typical of the age of 5–10 years and are, commonly, due to psoriasis or infective conditions. Nail tumors are rare. Acknowledgements None. Conflicts of interest There are no conflicts of interest.
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6. Wagner G, Sachse MM. Congenital malalignment of the big toe nail. J Dtsch Dermatol Ges 2012; 10:326–330. 7. Piraccini BM, Parente GL, Varotti E, et al. Congenital hypertrophy of the lateral nail folds of the hallux: clinical features and follow-up of seven cases. Pediatr Dermatol 2000; 17:348–351. 8. Jellinek NJ. Flaps in nail surgery. Dermatol Ther 2012; 25:535–544. 9. McIntosh I, Dreyer SD, Clough MV, et al. Mutation analysis of LMX1B gene in nail patella syndrome patients. Am J Hum Genet 1998; 63:1651–1658. 10. Bongers EM, Gubler MC, Knoers NV. Nail-patella syndrome: overview on clinical and molecular findings. Pediatr Nephrol 2002; 17:703–712. 11. Tosti A, de Farias DC, Murrell DF. Nail involvement in epidermolysis bullosa. Dermatol Clin 2010; 28:153–157. 12. Shah S, Boen M, Kenner-Bell B, et al. Pachyonychia congenita in pediatric patients: natural history, features, and impact. JAMA Dermatol 2014; 150: 146–153. 13. Eliason MJ, Leachman SA, Feng BJ, et al. A review of the clinical & phenotype of 254 patients with genetically confirmed pachyonychia congenita. J Am Acad Dermatol 2012; 67:680–686. A complete review of symptoms, diagnostic clues and details on quality of life of children with this disease. 14. Tosti A, Peluso AM, Zucchelli V. Clinical features and long term follow-up of 20 cases of parakeratosis pustulosa. Pediatr Dermatol 1998; 15:259–263. 15. Piraccini BM, Starace M. Nail psoriasis in special populations, children, && pregnant, elderly. In: Rigopoulos D, Tosti A. editors. Nail psoriasis: from A to Z. New York, NY: Springer; 2014 (in press). This recent work offers a good overview of clinical signs of nail psoriasis in extreme age populations. 16. Gordon KA, Vega JM, Tosti A. Trachyonychia: a comprehensive review. Indian J Dermatol Venereol Leprol 2011; 77:640–645. 17. Feely MA, Silverberg NB. Two cases of lichen striatus with prolonged active phase. Pediatr Dermatol 2014; 31:e67–68. 18. Youssef SM, Teng JM. Effective topical combination therapy for treatment of lichen striatus in children: a case series and review. J Drugs Dermatol 2012; 11:872–875. 19. Pandhi D, Singal A, Bhattacharya SN. Lichen planus in childhood: a series of 316 patients. Pediatr Dermatol 2014; 31:59–67. 20. Piraccini BM, Bruni F, Starace M. Dermoscopy of nonskin cancer nail disorders. Dermatol Ther 2012; 25:594–602. 21. Choi Y, Kim do H, Jin SY, et al. Topical immunotherapy with diphenylcyclopropenone is effective and preferred in the treatment of periungual warts. Ann Dermatol 2013; 25:434–439. 22. Durdu M, Ruocco V. Clinical and cytologic features of antibiotic-resistant acute paronychia. J Am Acad Dermatol 2014; 70:120–126. 23. Haneke E. Nail surgery. Clin Dermatol 2013; 31:516–525. This recent review on nail surgery moves step by step from the basic to the && more difficult surgery, giving helpful hints for the best result. 24. Piraccini BM, Bruni F, Starace M. Onychomycosis in children. Expert Rev Dermatol 2012; 7:558–569. & This recent review on onychomycosis in children covers epidemiology, clinical features, predisposing factors and management of this rare and overdiagnosed disease. 25. Tosti A, Baran R, Piraccini BM, et al. Nail matrix nevi: a clinical and histopathologic study of twenty-two patients. J Am Acad Dermatol 1996; 34(5 Pt 1):765–771. 26. Goettmann-Bonvallot S, Andre` J, Belaich S. Longitudinal melanonychia in children: a clinical and histopathologic study of 40 cases. J Am Acad Dermatol 1999; 41:17–22. 27. Tosti A, Piraccini BM, de Farias DC. Dealing with melanonychia. Semin Cutan Med Surg 2009; 28:49–54. 28. Tosti A, Piraccini BM, Cagalli A, et al. In situ melanoma of the nail unit in children: report of two cases in fair-skinned Caucasian children. Pediatr Dermatol 2012; 29:79–83. 29. DaCambra MP, Gupta SK, Ferri-de-Barros F. Subungual exostosis of the toes: a systemic review. Clin Orthop Relat Res 2014; 472: 1251–1259. & A systematic review of subungual exostosis, giving a guide to the best management.
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