Bullae are elevated, fluid-filled blisters ≥ 10 mm in diameter.
Linear IgA disease has two main clinical variants—bullous disease of childhood and adult linear IgA disease. Although they vary clinically in minor ways, their immunofluorescence patterns are identical. The IgA autoantibodies target several antigens within the dermal–epidermal junction.
Infections and penicillins trigger more than one fourth of childhood and adult cases. Vancomycin, diclofenac, nonsteroidal anti-inflammatory drugs (NSAIDs), captopril, and lithium also have been suggested as causes. Risk of linear IgA disease is increased in patients who have inflammatory bowel disease (possibly with a related pathophysiology that involves a generation of autoantibodies) or lymphoproliferative cancers (in adults) but not other autoimmune disorders.
In linear IgA disease, vesicular or bullous skin lesions occur frequently in a clustered (herpetiform) arrangement. In younger children, the face and perineum are often involved, and spread to the limbs, trunk, hands, feet, and scalp is common. In adults, the trunk is almost always involved, and the scalp, face, and limbs are often involved. Lesions are often pruritic and may burn. Mucosal involvement is common in both age groups; milia are not characteristic.
Drug-induced disease may be treated solely with withdrawal of the causative drug.
Mild disease can be treated with topical corticosteroids. Oral erythromycin can be used in children. Dapsone and sulfonamides (using doses and precautions similar to those for dermatitis herpetiformis) and colchicine are alternatives for all ages. Often the cutaneous lesions respond before the mucosal lesions. Spontaneous remission occurs in most patients after 3 to 6 years.