Anti-P200 Pemphigoid
A rare, acquired, subepidermal autoimmune bullous disease characterized by polymorphic cutaneous lesions (blisters, urticarial lesions or scars/milia) associated with imunoglubulin G deposition in the basement membrane zone. Lesions are frequently localized on extremities, trunk, palmoplantar and cephalic areas as well as mucous membranes.
Epidemiology
Approximately 115 cases been reported in the literature to date. A male predominant of about 2:1 is observed.
Clinical description
The disease predominantly affects elderly people (mean age 66 years, range 28-91). Cutaneous lesions are polymorphic, but typically include itchy erythematous lesions and tense blisters, vesicles, and erosions on trunk and extremities, with possibly predominant palmoplantar involvement. In some cases, patients can have annularly arranged lesions. Usually, lesions heal without scarring, and milia formation has only been reported in few cases. About half of the patients have mucosal involvement affecting either oral or anogenital mucosa, or both. In Japanese patients, coexisting (mostly preexisting) psoriasis may be present (30% of cases).
Etiology
The exact etiology is unknown, but may be related to laminin gamma-1, consistent with the identified characteristics of the p200 protein (an acidic non-collagenous N-linked glycoprotein localized within the lower lamina lucida outside of hemidesmosomes).
Diagnostic methods
Diagnosis is based on the combination of the clinical features and direct immunofluorescence microscopy showing linear deposits of IgG and/or C3 at the dermal-epidermal junction in an n-serrated pattern and is confirmed by detection of a 200-kDa band by immunoblotting of patients' serum on human dermal extracts. About 90% of patients' sera are positive for anti-laminin-gamma 1 reactivity on ELISA or immunoblotting.
Differential diagnosis
Differential diagnosis includes bullous pemphigoid, epidermolysis bullosa acquisita, mucous membrane pemphigoid, IgA linear bullous dermatosis, pemphigus herpetiform, and pemphigus.
Management and treatment
The treatment may follow that of bullous pemphigoid. Super-potent topical corticosteroids may be applied on the whole-body surface or tapering doses of prednisolone 0.5 mg/kg/day, frequently associated with dapsone. Doxycycline, azathioprine and ciclosporine can also be used.
Prognosis
Prognosis is variable. Most patients achieve complete remission on therapy. The use of systemic corticosteroid treatment may contribute to higher mortality rate in the older patients.