Photodermatology, Photoimmunology & Photomedicine
LETTER TO THE EDITOR
Phototherapy-induced erythema in patients with psoriasis and obesity treated with narrowband UVB phototherapy Eoin R. Storan1, Josette Galligan2 & Louise Barnes1
1
Department of Dermatology, St. James’s Hospital, Dublin, Ireland. 2 Department of Medical Physics, St. James’s Hospital, Dublin, Ireland.
Correspondence: Dr. Eoin Raymond Storan, M.B. B.Ch. B.A.O., Department of Dermatology, St. James’s Hospital, Dublin, Ireland. Tel: 00353 1 416 2102 Fax: 00353 1 428 4158 e-mail: [email protected]
Accepted for publication: 3 March 2014
Conflicts of interest: None declared.
To the Editor, The incidence of obesity is increasing across Britain, Europe and North America (1). Psoriasis is more common amongst patients with obesity (2), and previous studies have shown that obese patients tend to have more severe psoriasis (3, 4). Therefore, it is likely that in the future, a higher proportion of obese patients with psoriasis will require more intensive treatment modalities such as phototherapy for disease control. Current British Association of Dermatologists guidelines for dosimetry and calibration in narrowband UVB phototherapy (5) do not account for body habitus. Variations in irradiance with the delivery of phototherapy are influenced by many factors, such as hot and cold spots due to new lamps and failed lamps, as well as the distance of the target (i.e. the skin) from the UV lamps, which is affected by patient position in the UV cabinet and body shape and size (6). Clarkson et al. also concluded that the accuracy of cabinet dosimetry can be dependent on patient size (7). © 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd doi:10.1111/phpp.12121
UV dosing is calculated using designated patient irradiance, which is determined by measuring mean irradiance at chest, waist and knee levels in a person of average body size (8). There is currently no adjustment made for patients with non-average body type, such as those with obesity and increased waist circumference. Patients with increased body mass index (BMI) and waist circumference may be at a higher risk of developing phototherapyinduced erythema due to their closer proximity to the phototherapy bulbs. At our institution, we observed that patients who were obese more frequently developed erythema during their phototherapy course and consequently required more cautious escalations in their UV therapy dosing, with 10% increments rather than the standard 20% increments. In this pilot study, we aimed to determine if there was an association between BMI, waist circumference and incidence of phototherapy-related erythema in patients with psoriasis receiving narrowband UVB phototherapy. We performed a prospective analysis of all patients with psoriasis attending the dermatology phototherapy unit at our institution between 1 August 2012 and 28 February 2013. We recorded patient demographics (age, sex, skin type), weight, height, waist circumference, and the incidence and grade of phototherapy-induced erythema over the treatment period. Erythema response was recorded 48 h after treatment. No erythema was graded as E0; mild, barely perceptible asymptomatic erythema as E1; moderate, well-defined, asymptomatic erythema as E2; and severe, painful erythema, repeated symptomatic erythema and/or bullae as E3. Narrowband UVB was delivered using Waldmann 7001K cabinets (VillingenSchwenningen, Germany). Dermatology specialist nurses entered treatment times, not doses, and therefore internal cabinet sensors were not activated. Some patients had episodes of both E1 and E2 during their treatment course. Categorical variables were compared using the χ2-test. The level of significance was P < 0.05. 335
Letter to the Editor
Table 1. Distribution of erythema scores by waist circumference, body mass index and skin phototype Waist grade (cm) (M, F)
Total (n = 36)†
E1
E2
10% increments
MED
≥ 107, ≥ 101 ≥ 99 to < 107, ≥ 92 to 101 ≥ 92 to < 99, ≥ 84 to 92 ≥ 84 to < 92, ≥ 76 to 84 < 84, < 76 BMI (kg/m2) Obese (> 30) Overweight (25–29.9) Normal (18.5–24.9) Underweight (< 18.5) Skin phototype‡ Melano-incompetent Melanocompetent
7 5 8 8 8 Total (n = 38) 8 13 15 2 Total (n = 38) 33 5
5 (71.4%) 2 (40%) 4 (50%) 3 (37.5%) 5 (62.5%) E1 7 (87.5%) 5 (38.5%) 6 (40%) 0 E1 17 2
5 (71.4%) 3 (60%) 3 (37.5%) 4 (50%) 3 (37.5%) E2 4 (50%) 9 (69.2%) 7 (46.6%) 1 (50%) E2 18 0
5 (71.4%) 0 4 (50%) 1 (12.5%) 1 (12.5%) 10% increments 4 (50%) 3 (23%) 3 (20%) 0 10% increments 9 2
2 (28.6%) 2 (40%) 4 (50%) 1 (12.5%) 0 MED 2 (25%) 3 (23%) 4 (26.7%) 0 MED 9 0
The unit of analysis in the table is a single patient. Values are number (percentage). † Waist circumference was unavailable in 2 patients. ‡ Fitzpatrick phototype. BMI, body mass index; E1 & E2, grade 1 and grade 2 erythema; MED, minimal erythema dose.
In total, 38 patients were included in the study. There were 8 obese patients (BMI > 30), of whom 7 (87.5%) had at least one episode of E1 and 4 (50%) had at least one episode of E2. Of note, 50% of obese patients required 10% dose increments during their course of phototherapy. There were 13 patients who were overweight (BMI 25–29.9), of whom 5 (38.5%) had at least one episode of E1 and 9 (69.2%) had at least one episode of E2. There were 15 patients with normal BMI (BMI 18.5–24.9), of whom 6 (40%) had an E1 and 7 (46.6%) had an E2. Of these, 3 patients (20%) required 10% dose increments during their phototherapy. We compared the incidence of erythema between patients with normal BMI and obese patients, and a statistically significant difference was noted in the incidence of E1 in patients with obesity (P = 0.0043). The majority of patients (86.6%) were melanoincompetent (Fitzpatrick phototype I and II). There were 5 patients who were melanocompetent (Fitzpatrick phototype III and above). Of these, 1 patient had a normal BMI, 3 were overweight and 1 was obese. Of patients with the largest waist circumference (≥ 107 cm in men, ≥ 101 cm in women; n = 7), 5 (71.4%) had an E1 and 5 (71.4%) had an E2. Five of these patients (71.4%) received phototherapy with 10% dose increments. Of patients with the smallest waist circumference (< 84 cm in men, < 76 cm in women; n = 8), 5 (62.5%) had an E1 and 3 (37.5%) had an E2. Only 1 patient (12.5%) received phototherapy with 10% dose increments. Comparison of waist circumference groups did not show any statistically significant differences.
The anatomic location of erythema was not recorded in 26 patients (68.4%), making interpretation of the anatomical distribution difficult. Of the 12 patients where the site of erythema was recorded, erythema was located on the chest in 5 patients, on the back in 5 patients, and on the abdomen and the thighs in 1 patient each. See Table 1 for further data. Our data are limited by the low number of patients, and not all patients had a minimal erythema dose assessed prior to starting phototherapy. Patients with increased BMI and larger waist circumferences had a trend towards a higher incidence of phototherapy-related erythema. They subsequently required dose escalation of phototherapy in 10% increments more often compared with those with normal BMI and waist circumferences. The incidence of erythema reached statistical significance for E1 in patients with obesity as compared with those with normal BMI. The higher erythema scores in obese patients could be due to their closer proximity to the phototherapy bulbs or to altered photoadaptation in patients with obesity. While the development of mild erythema during treatment can signify that patients are receiving adequate doses to treat their psoriasis, it may also indicate that patients are more likely to develop severe erythema, which is supported by a trend towards higher E2 scores noted in patients with obesity. We propose that patients with obesity and increased waist circumference may be at a higher risk of phototherapy-induced erythema as a complication of their treatment. Development of grade 2 erythema necessitates
336
Photodermatol Photoimmunol Photomed 2014; 30: 335–337 © 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd
Letter to the Editor
the withholding of a session of phototherapy, resulting in greater patient morbidity and also longer durations of treatment and consequently inconvenience to patients, as well as higher costs to the medical institution (9).
In light of the growing incidence of obesity, future treatment regimens may require dose adjustment for patients with increased BMI to help reduce this complication.
REFERENCES 1. Flegal KM, Carroll MD, Kuczmarski RJ, Johnson CL. Overweight and obesity in the United States: prevalence and trends, 1960– 1994. Int J Obes Relat Metab Disord 1998; 22: 39–47. 2. Wolk K, Mallbris L, Larsson P, Rosenblad A, Vingard E, Stahle M. Excessive body weight and smoking associates with a high risk of onset of plaque psoriasis. Acta Derm Venereol 2009; 89: 492–497. 3. Herron MD, Hinckley M, Hoffman MS et al. Impact of obesity and smoking on psoriasis presentation and management. Arch Dermatol 2005; 141: 1527–1534.
4. Hamminga EA, van der Lely AJ, Neumann HA, Thio HB. Chronic inflammation in psoriasis and obesity: implications for therapy. Med Hypotheses 2006; 67: 768– 773. 5. Taylor DK, Anstey AV, Coleman AJ et al. Guidelines for dosimetry and calibration in ultraviolet radiation therapy: a report of a British Photodermatology Group workshop. Br J Dermatol 2002; 146: 755–763. 6. Amatiello H, Martin CJ. Ultraviolet phototherapy: review of options for cabin dosimetry and operation. Phys Med Biol 2006; 51: 299–309.
Photodermatol Photoimmunol Photomed 2014; 30: 335–337 © 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd
7. Clarkson DM, Franks L. The use of a simulated body shape for determination of patient dosimetry within whole body ultraviolet treatment cabinets. Phys Med Biol 2006; 51: N51–N58. 8. Moseley H. Scottish UV dosimetry guidelines, ‘ScUViDo’. Photodermatol Photoimmunol Photomed 2001; 17: 230– 233. 9. Langan SM, Heerey A, Barry M, Barnes L. Cost analysis of narrowband UVB phototherapy in psoriasis. J Am Acad Dermatol 2004; 50: 623–626.
337
This document is a scanned copy of a printed document. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material.
LETTER TO THE EDITOR
Phototherapy-induced erythema in patients with psoriasis and obesity treated with narrowband UVB phototherapy Eoin R. Storan1, Josette Galligan2 & Louise Barnes1
1
Department of Dermatology, St. James’s Hospital, Dublin, Ireland. 2 Department of Medical Physics, St. James’s Hospital, Dublin, Ireland.
Correspondence: Dr. Eoin Raymond Storan, M.B. B.Ch. B.A.O., Department of Dermatology, St. James’s Hospital, Dublin, Ireland. Tel: 00353 1 416 2102 Fax: 00353 1 428 4158 e-mail: [email protected]
Accepted for publication: 3 March 2014
Conflicts of interest: None declared.
To the Editor, The incidence of obesity is increasing across Britain, Europe and North America (1). Psoriasis is more common amongst patients with obesity (2), and previous studies have shown that obese patients tend to have more severe psoriasis (3, 4). Therefore, it is likely that in the future, a higher proportion of obese patients with psoriasis will require more intensive treatment modalities such as phototherapy for disease control. Current British Association of Dermatologists guidelines for dosimetry and calibration in narrowband UVB phototherapy (5) do not account for body habitus. Variations in irradiance with the delivery of phototherapy are influenced by many factors, such as hot and cold spots due to new lamps and failed lamps, as well as the distance of the target (i.e. the skin) from the UV lamps, which is affected by patient position in the UV cabinet and body shape and size (6). Clarkson et al. also concluded that the accuracy of cabinet dosimetry can be dependent on patient size (7). © 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd doi:10.1111/phpp.12121
UV dosing is calculated using designated patient irradiance, which is determined by measuring mean irradiance at chest, waist and knee levels in a person of average body size (8). There is currently no adjustment made for patients with non-average body type, such as those with obesity and increased waist circumference. Patients with increased body mass index (BMI) and waist circumference may be at a higher risk of developing phototherapyinduced erythema due to their closer proximity to the phototherapy bulbs. At our institution, we observed that patients who were obese more frequently developed erythema during their phototherapy course and consequently required more cautious escalations in their UV therapy dosing, with 10% increments rather than the standard 20% increments. In this pilot study, we aimed to determine if there was an association between BMI, waist circumference and incidence of phototherapy-related erythema in patients with psoriasis receiving narrowband UVB phototherapy. We performed a prospective analysis of all patients with psoriasis attending the dermatology phototherapy unit at our institution between 1 August 2012 and 28 February 2013. We recorded patient demographics (age, sex, skin type), weight, height, waist circumference, and the incidence and grade of phototherapy-induced erythema over the treatment period. Erythema response was recorded 48 h after treatment. No erythema was graded as E0; mild, barely perceptible asymptomatic erythema as E1; moderate, well-defined, asymptomatic erythema as E2; and severe, painful erythema, repeated symptomatic erythema and/or bullae as E3. Narrowband UVB was delivered using Waldmann 7001K cabinets (VillingenSchwenningen, Germany). Dermatology specialist nurses entered treatment times, not doses, and therefore internal cabinet sensors were not activated. Some patients had episodes of both E1 and E2 during their treatment course. Categorical variables were compared using the χ2-test. The level of significance was P < 0.05. 335
Letter to the Editor
Table 1. Distribution of erythema scores by waist circumference, body mass index and skin phototype Waist grade (cm) (M, F)
Total (n = 36)†
E1
E2
10% increments
MED
≥ 107, ≥ 101 ≥ 99 to < 107, ≥ 92 to 101 ≥ 92 to < 99, ≥ 84 to 92 ≥ 84 to < 92, ≥ 76 to 84 < 84, < 76 BMI (kg/m2) Obese (> 30) Overweight (25–29.9) Normal (18.5–24.9) Underweight (< 18.5) Skin phototype‡ Melano-incompetent Melanocompetent
7 5 8 8 8 Total (n = 38) 8 13 15 2 Total (n = 38) 33 5
5 (71.4%) 2 (40%) 4 (50%) 3 (37.5%) 5 (62.5%) E1 7 (87.5%) 5 (38.5%) 6 (40%) 0 E1 17 2
5 (71.4%) 3 (60%) 3 (37.5%) 4 (50%) 3 (37.5%) E2 4 (50%) 9 (69.2%) 7 (46.6%) 1 (50%) E2 18 0
5 (71.4%) 0 4 (50%) 1 (12.5%) 1 (12.5%) 10% increments 4 (50%) 3 (23%) 3 (20%) 0 10% increments 9 2
2 (28.6%) 2 (40%) 4 (50%) 1 (12.5%) 0 MED 2 (25%) 3 (23%) 4 (26.7%) 0 MED 9 0
The unit of analysis in the table is a single patient. Values are number (percentage). † Waist circumference was unavailable in 2 patients. ‡ Fitzpatrick phototype. BMI, body mass index; E1 & E2, grade 1 and grade 2 erythema; MED, minimal erythema dose.
In total, 38 patients were included in the study. There were 8 obese patients (BMI > 30), of whom 7 (87.5%) had at least one episode of E1 and 4 (50%) had at least one episode of E2. Of note, 50% of obese patients required 10% dose increments during their course of phototherapy. There were 13 patients who were overweight (BMI 25–29.9), of whom 5 (38.5%) had at least one episode of E1 and 9 (69.2%) had at least one episode of E2. There were 15 patients with normal BMI (BMI 18.5–24.9), of whom 6 (40%) had an E1 and 7 (46.6%) had an E2. Of these, 3 patients (20%) required 10% dose increments during their phototherapy. We compared the incidence of erythema between patients with normal BMI and obese patients, and a statistically significant difference was noted in the incidence of E1 in patients with obesity (P = 0.0043). The majority of patients (86.6%) were melanoincompetent (Fitzpatrick phototype I and II). There were 5 patients who were melanocompetent (Fitzpatrick phototype III and above). Of these, 1 patient had a normal BMI, 3 were overweight and 1 was obese. Of patients with the largest waist circumference (≥ 107 cm in men, ≥ 101 cm in women; n = 7), 5 (71.4%) had an E1 and 5 (71.4%) had an E2. Five of these patients (71.4%) received phototherapy with 10% dose increments. Of patients with the smallest waist circumference (< 84 cm in men, < 76 cm in women; n = 8), 5 (62.5%) had an E1 and 3 (37.5%) had an E2. Only 1 patient (12.5%) received phototherapy with 10% dose increments. Comparison of waist circumference groups did not show any statistically significant differences.
The anatomic location of erythema was not recorded in 26 patients (68.4%), making interpretation of the anatomical distribution difficult. Of the 12 patients where the site of erythema was recorded, erythema was located on the chest in 5 patients, on the back in 5 patients, and on the abdomen and the thighs in 1 patient each. See Table 1 for further data. Our data are limited by the low number of patients, and not all patients had a minimal erythema dose assessed prior to starting phototherapy. Patients with increased BMI and larger waist circumferences had a trend towards a higher incidence of phototherapy-related erythema. They subsequently required dose escalation of phototherapy in 10% increments more often compared with those with normal BMI and waist circumferences. The incidence of erythema reached statistical significance for E1 in patients with obesity as compared with those with normal BMI. The higher erythema scores in obese patients could be due to their closer proximity to the phototherapy bulbs or to altered photoadaptation in patients with obesity. While the development of mild erythema during treatment can signify that patients are receiving adequate doses to treat their psoriasis, it may also indicate that patients are more likely to develop severe erythema, which is supported by a trend towards higher E2 scores noted in patients with obesity. We propose that patients with obesity and increased waist circumference may be at a higher risk of phototherapy-induced erythema as a complication of their treatment. Development of grade 2 erythema necessitates
336
Photodermatol Photoimmunol Photomed 2014; 30: 335–337 © 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd
Letter to the Editor
the withholding of a session of phototherapy, resulting in greater patient morbidity and also longer durations of treatment and consequently inconvenience to patients, as well as higher costs to the medical institution (9).
In light of the growing incidence of obesity, future treatment regimens may require dose adjustment for patients with increased BMI to help reduce this complication.
REFERENCES 1. Flegal KM, Carroll MD, Kuczmarski RJ, Johnson CL. Overweight and obesity in the United States: prevalence and trends, 1960– 1994. Int J Obes Relat Metab Disord 1998; 22: 39–47. 2. Wolk K, Mallbris L, Larsson P, Rosenblad A, Vingard E, Stahle M. Excessive body weight and smoking associates with a high risk of onset of plaque psoriasis. Acta Derm Venereol 2009; 89: 492–497. 3. Herron MD, Hinckley M, Hoffman MS et al. Impact of obesity and smoking on psoriasis presentation and management. Arch Dermatol 2005; 141: 1527–1534.
4. Hamminga EA, van der Lely AJ, Neumann HA, Thio HB. Chronic inflammation in psoriasis and obesity: implications for therapy. Med Hypotheses 2006; 67: 768– 773. 5. Taylor DK, Anstey AV, Coleman AJ et al. Guidelines for dosimetry and calibration in ultraviolet radiation therapy: a report of a British Photodermatology Group workshop. Br J Dermatol 2002; 146: 755–763. 6. Amatiello H, Martin CJ. Ultraviolet phototherapy: review of options for cabin dosimetry and operation. Phys Med Biol 2006; 51: 299–309.
Photodermatol Photoimmunol Photomed 2014; 30: 335–337 © 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd
7. Clarkson DM, Franks L. The use of a simulated body shape for determination of patient dosimetry within whole body ultraviolet treatment cabinets. Phys Med Biol 2006; 51: N51–N58. 8. Moseley H. Scottish UV dosimetry guidelines, ‘ScUViDo’. Photodermatol Photoimmunol Photomed 2001; 17: 230– 233. 9. Langan SM, Heerey A, Barry M, Barnes L. Cost analysis of narrowband UVB phototherapy in psoriasis. J Am Acad Dermatol 2004; 50: 623–626.
337
This document is a scanned copy of a printed document. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material.
