CD05 The hazards of patch testing in a patient with Hailey–Hailey disease

Abstract The tendency to intraepidermal acantholysis seen in Hailey–Hailey disease, due to weakened desmosomal adhesions, can present problems when patch testing a patient with the disease. A 51-year-old man with Hailey–Hailey disease affecting the axillae, groins and scrotum had tried various topical medicaments, none of which had helped him particularly. He was patch tested to the British Society for Cutaneous Allergy standard, cosmetic/toiletry, medicament and targeted clothing series together with his own personal care products, using Finn chambers on Scanpor®. Despite being very careful about removing the tapes on day 2, he developed erosions similar to Hailey–Hailey lesions but without pustules or vesicles, under the tape. The erosions developed more on the central back than laterally, but not where the Finn chambers had been. The lesions healed within 2 weeks. It is postulated that the lesions were related to frictional stress that might be greater in the central back than at lateral locations and the underlying structural defects. Patch tests showed no allergic positives. Occasional cases of a similar nature have been reported. In one report, a history of previous tape irritation in a patient with Hailey–Hailey disease gave an indication that patch testing might be complicated by this phenomenon (Podjasek JO, Cook-Norris RH, Brewer JD. Painful erosions induced by patch testing in a patient with Hailey–Hailey disease. Int J Dermatol 2012; 52: 123–4). However, there were no noted issues in several other individuals with Hailey–Hailey disease the authors had previously patch tested. Walker and Beck even revealed undiagnosed Hailey–Hailey disease by observing this type of reaction complicating patch testing (Walker SL, Beck MH. Undiagnosed Hailey–Hailey disease causing painful erosive skin changes during patch testing. Br J Dermatol 2005; 153: 233–4). The message from this and other cases is that patch testing in patients with Hailey–Hailey disease needs to be done with the utmost care, perhaps applying the allergens in a targeted manner and using body locations other than the usual back site – where pressure and friction might be less. As the Finn chamber sites are protected from lesional development, allergic reactions should be visible.