¿Es útil la determinación de la dosis eritematógena mínima previa a la fototerapia ultravioleta B de banda estrecha? / Is it Useful to Calculate Minimal Erythema Dose Before Narrowband UV-B Phototherapy?

Introducción y objetivos: La dosis de inicio en la fototerapia UVB de banda estrecha (UVBBE) viene determinada por el fototipo o por la determinación de la dosis eritematógena mínima (DEM). El cálculo de la DEM identifica pacientes con fotosensibilidad no sospechada. El objetivo de nuestro estudio es conocer la influencia que puedan tener en una DEM disminuida los fármacos fotosensibilizantes concomitantes, el diagnóstico, la asociación con acitretina en pacientes con psoriasis y evidenciar si la DEM alterada provoca más reacciones adversas y más graves. Material y métodos: Se trata de un estudio observacional de una cohorte retrospectiva desde el período comprendido entre el 1 de febrero de 2009 al 31 de marzo de 2015. La determinación de la DEM se categorizó en DEM normal o patológica. Resultados: Trescientos dos pacientes con distintas dermatosis inician UVBBE en función de la DEM. No se han encontrado diferencias entre el grupo con DEM patológica respecto al normal, ni en el número de fármacos consumidos (p = 0,071), ni en el potencial fotosensibilizante (p = 0,806). El análisis multivariante ajustado por edad, sexo y fototipo reveló que la psoriasis es un factor protector de DEM patológica (OR = 0,31 [IC 95%: 0,16-0,58]). No se encontró riesgo significativo de eritema ni prurito en los pacientes con DEM alterada OR = 1,68 (IC 95%: 0,91-3,29) y OR = 2,04 (IC 95%: 0,99-4,22), respectivamente. Conclusiones: La psoriasis protege de tener una DEM patológica. Si bien el eritema y el prurito fueron más frecuentes en los pacientes con DEM patológica, las diferencias no fueron estadísticamente significativas (AU)

Introduction and objectives: The starting dose for narrowband UV-B phototherapy is determined by a patient's skin phototype or minimal erythema dose (MED). Calculation of MED identifies patients with unsuspected photosensitivity. The aim of this study was to investigate the influence of factors such as concomitant use of photosensitizing agents, diagnosis, and combination with acitretin in patients with psoriasis on the frequency and severity of adverse effects in patients with a low MED to narrowband UV-B phototherapy. Material and methods: We undertook a retrospective observational cohort study between February 1, 2009 and March 31, 2015. MED values were classified as normal or low. Results: In total, 302 patients with different skin conditions started narrowband UV-B phototherapy at a dose determined by their MED. No differences were found between patients with a low MED and those with a normal MED for number of drugs taken (P = .071) or use of photosensitizing agents (P = 0.806). Following adjustment for age, sex, and phototype, the multivariate analysis showed that psoriasis exerted a protective effect against a low MED (OR = 0.31 [95% CI, 0.16-0.58]). No significant risk of erythema or pruritus was detected in patients with a low MED (OR = 1.68; 95% CI, 0.91-3.29 and OR = 2.04; 95% CI, 0.99-4.22, respectively). Conclusions: Psoriasis protects against a low MED. Although erythema and pruritus were more common in patients with a low MED, the differences were not significant (AU)

Is it Useful to Calculate Minimal Erythema Dose Before Narrowband UV-B Phototherapy? / ¿Es útil la determinación de la dosis eritematógena mínima previa a la fototerapia ultravioleta B de banda estrecha?

INTRODUCTION AND OBJECTIVES: The starting dose for narrowband UV-B phototherapy is determined by a patient's skin phototype or minimal erythema dose (MED). Calculation of MED identifies patients with unsuspected photosensitivity. The aim of this study was to investigate the influence of factors such as concomitant use of photosensitizing agents, diagnosis, and combination with acitretin in patients with psoriasis on the frequency and severity of adverse effects in patients with a low MED to narrowband UV-B phototherapy. MATERIAL AND METHODS: We undertook a retrospective observational cohort study between February 1, 2009 and March 31, 2015. MED values were classified as normal or low. RESULTS: In total, 302 patients with different skin conditions started narrowband UV-B phototherapy at a dose determined by their MED. No differences were found between patients with a low MED and those with a normal MED for number of drugs taken (P=.071) or use of photosensitizing agents (P=0.806). Following adjustment for age, sex, and phototype, the multivariate analysis showed that psoriasis exerted a protective effect against a low MED (OR=0.31 [95% CI, 0.16-0.58]). No significant risk of erythema or pruritus was detected in patients with a low MED (OR=1.68; 95% CI, 0.91-3.29 and OR=2.04; 95% CI, 0.99-4.22, respectively). CONCLUSIONS: Psoriasis protects against a low MED. Although erythema and pruritus were more common in patients with a low MED, the differences were not significant.