Screening for Adrenal Insufficiency During Dermocorticoid Reduction in Bullous Pemphigoid (BP)

Overview

The braking of the corticotropic axis is well established during the induction phase of superpotent topical corticosteroid therapy (clobetasol propionate) in bullous pemphigoid (BP). But the evolution of the corticotropic axis in the following months, especially during the tapering of topical steroids has never been studied. The objective of this study is to evaluate the prevalence of adrenal insufficiency during the topical corticosteroid therapy tapering in patients treated according to current recommendations. The secondary objectives of the study are : * to evaluate the presence of other clinico-biological signs of adrenal insufficiency (hypotension, hypoglycemia and/or hyponatremia) * to compare the characteristics of patients with adrenal insufficiency to those without in order to identify potential risk factors for adrenal insufficiency in BP.

BP is the most common autoimmune bullous dermatosis, with 400 incident cases per year in France and an estimated annual mortality rate of 30%. It affects very old and frail patients, with an average age of 80 years. High potency topical corticosteroids is the first line therapy, with a high dose applied to the entire tegument for at least 4 months according to current guidelines. In this high potency topical therapy, a braking of the corticotropic axis has been reported during the initial phase of treatment, at the highest doses, explained by the transdermal and systemic passage of dermocorticoids. Monitoring if natural cortisol secretion will start again has never been studied during the tapering of topical corticosteroid therapy, and its under-diagnosis could be deleterious for patients. The French guidelines currently recommends hydrocortisone supplementation at the time of waning from less than 20 g of clobetasol propionate per week, but without any data supporting it. Prospective multicenter study coordinated by the Bordeaux Dermatology Department and conducted within the French study Group on autoimmune bullous diseases, will aim to include 50 patients with a diagnosis of bullous pemphigoid and treated according to recommendations. Serum dosage of Cortisol concentration will be measured on two occasions, at the last two steps of the corticosteroid tapering (20-40g, twice a week and 20-40g once a week). If necessary, a Synacthen® test will be performed in addition.