Fibrillar-Type Dermatitis Herpetiformis

Dermatitis herpetiformis (DH) is a rare, intensely pruritic cutaneous manifestation of celiac disease (CD), typically presenting with excoriated papulovesicular lesions on extensor surfaces. DH is associated with IgA autoantibodies against epidermal transglutaminase (eTG), which form granular immune deposits in the papillary dermis and induce subepidermal blistering. Histopathology usually shows papillary dermal microabscesses and granular IgA deposits on direct immunofluorescence. We describe two patients with atypical DH featuring fibrillar, rather than granular, IgA deposits and no evidence of CD. Importantly, in both patients, we are the first to show that eTG did not colocalize with the fibrillar IgA deposits in the skin. Awareness of this pattern is essential to avoid misdiagnosis and potentially unwarranted gluten-free diets, as fibrillar DH is often unrelated to CD.

Abstract from PubMed