Fibrillar IgA deposition may be associated with atypical dermatitis herpetiformis — a report of two cases

Abstract

We report two cases of known dermatitis herpetiformis (DH) who presented with atypical clinical dermatological features. The first case, a 31-year-old woman, presented with an itchy urticated eruption on the abdomen and trunk, while the second case, a 50-year-old woman developed a scaly psoriasiform eruption on the extensor aspects of her knees and elbows. In each case, direct immunofluorescence of a perilesional skin biopsy showed a fibrillar pattern of IgA deposition at the basement membrane zone. Pre-embedding immunoelectron microscopy of these 2 specimens, using a 1 nm gold probe and silver enhancement, showed colloid gold particle deposition around microfibril bundles in the dermal papillae. Recent studies have shown that fibrillin, a 350 kDa glycoprotein, is also associated with these microfibril bundles.Serological tissue typing in our first case confirmed the presence of HLA-B8, B18, DR3 and DQw2 antigens consistent with dermatitis herpetiformis. In the second case, there was a notable absence of the antigens B17 and B27 typically found in psoriasis but HLA-A1, B8 and DQ1 antigens were present, as commonly seen in dermatitis herpetiformis. Our findings would suggest that cases of dermatitis herpetiformis with fibrillar IgA deposition at the BMZ on direct IMF may show an atypical clinical presentation. In addition, our imunoelectron microscopy findings may provide a further clue to an ultrastructural abnormality in this disease.