P12 A flare of dermatitis herpetiformis precipitated by etanercept

Abstract

Abstract We report the case of a 79-year-old man who presented with an acute, intensely pruritic, widespread rash, which, on examination, consisted of symmetrical, haemorrhagic nodules and vesicles with some desquamation affecting the extensor surfaces of the arms, flexor surfaces of the legs and the natal cleft. He had a history of coeliac disease (for which he had adhered to a strict gluten-free diet since 1997) and rheumatoid arthritis. He had his first dose of the anti-tumour necrosis factor (TNF) agent etanercept prior to this episode to manage his arthritis. A punch biopsy for histopathology showed subepidermal blisters with a predominance of neutrophils. Eosinophils were also present to the level of the eccrine coils within the dermis, with eosinophilic flame figures but no eosinophil spongiosis at the edges of the blister. Direct immunofluorescence showed granular IgM and IgA in the dermal papillae, and a similar reaction was seen with fibrinogen. These histological findings were strongly suggestive of dermatitis herpetiformis (DH). Owing to diagnostic uncertainty on presentation, initial treatment was with high-dose topical steroids and emollient. and a yellow card was completed. Since this presentation, he has had no further flares and has not required dapsone. Multidisciplinary team discussion decided that the patient should avoid other anti-TNF treatments, but he has found relief for multiple months with rituximab and has had no cutaneous adverse events on this agent. The aetiology of DH following anti-TNF treatment is not immediately clear. Increased immunogenicity and cytokine release have been hypothesized to be part of the pathology of many adverse reactions to anti-TNF agents. It is conceivable that the cytokine release ordinarily seen in DH is replicated by the administration of anti-TNF agents. There have been many cases of anti-TNF agents leading to worsening eczema and psoriasis. Interestingly, these conditions have been found to upregulate TNF-α, a feature that is also seen in DH. This appears to be the first case described in the literature of etanercept-induced DH. A reaction with infliximab was reported in 2008, with a similar rash and histology consistent with DH, but it differed as the patient had no prior diagnosis of coeliac disease and presented after their second dose (Marakli SS, Uzun S, Ozbek S, Tuncer I. Dermatitis herpetiformis in a patient receiving infliximab for ankylosing spondylitis. Eur J Dermatol 2008; 18:88–9).