Development of Dermatitis Herpetiformis in Chronic Plaque Psoriasis

Chronic plaque psoriasis is often associated with autoimmune bullous diseases. Dermatitis herpetiformis (DH) is a rare immunobullous disease that has been linked to celiac disease (CD). To our knowledge, the coexistence of psoriasis and DH is uncommon, and has only been described in anecdotal reports. We report a case of chronic plaque psoriasis complicated by DH in a 60-year-old patient with no known history of CD or associated symptoms. In our patient, DH presented atypically as multiple vesicles along the edges of psoriatic plaques located on the back and hips, and as vesiculobullous eruptions on the fingers. The patient was successfully treated with a combination of dapsone and a gluten-free diet for DH, and secukinumab for psoriasis. This case highlights the importance of screening for CD in patients with psoriasis, as well as other concomitant autoimmune diseases. A gluten-free diet should be trialled in psoriatic patients with positive CD serology.