Bullae are elevated, fluid-filled blisters ≥ 10 mm in diameter.
Pemphigus foliaceus usually occurs in middle-aged patients, affecting men and women in equal numbers. An endemic form of pemphigus foliaceus, fogo selvagem, occurs in younger adults and children, particularly in South America. Pemphigus foliaceus may occur after use of penicillamine, nifedipine, or captopril.
Pemphigus erythematosus, a form of pemphigus foliaceus localized to the cheeks, has immunologic features of pemphigus and lupus erythematosus (IgG and C3 deposition on keratinocyte surfaces and basement membrane zone with circulating antinuclear antibodies); however, patients rarely are diagnosed with both diseases concurrently.
Pemphigus foliaceus is mediated by IgG autoantibody against desmoglein 1 (Dsg1), a transmembrane glycoprotein cadherin important to cell–cell adhesion and signaling between keratinocytes (1; see figure Skin cleavage levels in pemphigus and bullous pemphigoid).
Skin cleavage levels in pemphigus and bullous pemphigoid
1. Russo I, De Siena FP, Saponeri A, et al: Evaluation of anti-desmoglein-1 and anti-desmoglein-3 autoantibody titers in pemphigus patients at the time of the initial diagnosis and after clinical remission. Medicine (Baltimore) 96(46):e8801, 2017. doi: 10.1097/MD.0000000000008801
The primary lesion is a flaccid vesicle or bulla, but due to the superficial location of the epidermal split, lesions tend to rupture, so intact bullae or vesicles are rarely evident on examination. Instead, well-demarcated, scattered, crusted, erythematous lesions are common on the face, scalp, and upper trunk. Mucosal involvement is rare. Skin lesions can burn and cause pain, but patients are typically not severely ill. Pemphigus erythematosus tends to affect the malar cheeks.
Diagnosis of pemphigus foliaceus is by biopsy of a lesion and adjacent (perilesional) unaffected skin that shows IgG autoantibodies against the keratinocyte cell surface via direct immunofluorescence. Autoantibodies to desmoglein 1 can be detected in serum via direct immunofluorescence, indirect immunofluorescence, and enzyme-linked immunosorbent assay (ELISA).
If the disease is localized and not severe, high-potency topical corticosteroids are typically effective. More widespread or severe cases require systemic corticosteroids plus, at times, other immunosuppressive therapies, such as rituximab, plasma exchange, methotrexate, mycophenolate mofetil, or azathioprine. Topical calcineurin inhibitors have also been used.
Limited studies suggest that addition of a combination of tetracycline 500 mg orally 4 times a day or doxycycline 100 mg orally twice a day and nicotinamide 500 mg orally 3 times a day may be effective in some people.