LAD is characterized by the deposition of IgA rather than IgG at the basement membrane zone, and the clinical manifestations may resemble either dermatitis herpetiformis or pemphigoid. The cause of the majority of cases is unknown, but a minority of cases have been drug induced.As in MMP, the antigens associated with LAD are heterogeneous and may be found in either the lamina lucida or lamina densa portions of the basement membrane.
The skin lesions of LAD may resemble those observed in patients with dermatitis herpetiformis, which are characterized by pruritic papules and blisters at sites of trauma such as the knees and elbows. Other patients have bullous skin lesions similar to those seen in patients with bullous pemphigoid.Oral lesions are common in LAD and may be seen in up to 70% of patients. These lesions are clinically indistinguishable from the oral lesions of MMP, with blisters and erosions of the mucosa frequently accompanied by desquamative gingivitis.
The oral lesions of LAD may be managed with the use of topical steroids, but dapsone is effective therapy for more severe cases. Resistant cases may require systemic corticosteroids.