CBDC is another blistering disorder, which chiefly affects children below the age of 5 years. It is characterized by the deposition of IgA antibodies in the basement membrane zone,
which are detected by direct immunofluorescence on the epidermal side of salt-split skin or mucosa. The onset of the disease may be precipitated by an upper respiratory infection or drug therapy.The characteristic lesion of CBDC is a cluster of vesicles and bullae on an inflamed base. The genital region is involved; conjunctival, rectal, and oral lesions may also be present. Oral mucosal involvement is present in up to 50% of cases, and the oral lesions are similar to those observed in patients with MMP.
Diagnosis is made by biopsy demonstrating a subepithelial lesion on routine histology and by deposition of IgA in the basement membrane zone on direct immunofluorescence. Indirect immunofluorescence demonstrates circulating IgA in 80% of cases.This disease is self-limiting, and the lesions characteristically heal within 2 years. As with LAD, the lesions are responsive to sulfapyridine or dapsone therapy. Corticosteroids may be required for severe cases.