Bullous pemphigoid with prominent milium formation.

Milia are very common superficial keratinous cysts, clinically seen as pearly white dome-shaped lesions with a diameter of 1-2 mm. Bullous pemphigoid (BP) is an autoimmune bullous disease characterized clinically by tense bullae on the extremities and trunk. The major target autoantigens of BP are BP180 and BP230. We report a 55-year-old Polish BP patient presenting prominent milium formation. Physical examination revealed multiple tense bullae on the erythemas scattered on the extremities and trunk. Histopathology revealed subepidermal blisters with infiltration of eosinophils in and around the blister. Direct immunofluorescence showed IgG and C3 depositions at basement membrane zone. Although indirect immunofluorescence of normal human skin sections was negative, indirect immunofluorescence of salt-split skin sections showed IgG reactivity with epidermal side. Immunoblotting showed that IgG antibodies in the serum reacted with recombinant protein of the BP180 NC16a domain. ELISA of BP180, but not BP230 and type VII collagen, showed positive results. Several months after oral prednisolone therapy, multiple large milia appeared on the healed BP lesions. Histopathology showed cysts with flaky keratinous inclusions in the mid-dermis. We diagnosed the patient as BP with milia. Since milia are occasionally found in BP, they are not a definite differential criterion from epidermolysis bullosa acquisita.