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1.2.5 Pemphigus Vulgaris
Synonyms
Epidemiology
Incidence of 2-7 new cases per million per year. F = M, 30-60 years. Ethnic variations.
Definition
Autoimmune disease with intraepidermal blister formation.
Aetiology & Pathogenesis
Loss of cell adhesion within epidermis (Acantholysis) and blister formation by circulating autoantibodies against desmosomal proteins (desmogleins 1 and 3).
Signs & Symptoms
Pemphigus vulgaris: onset with oral erosions in more than 50% of cases, later superficial, fragile blisters with rapid transition to crusted erosions. The lesions usually develop in non-inflamed skin. Nikolski's signs positive (Nikolski I: blisters induced by rubbing normal skin. Nikolski II: existing blisters extend with lateral pressure). Pemphigus foliaceus: It manifests with impetigo-like crusted erosions usually on an erythematous base, and usually starts in seborrheic areas. Mucosae are usually spared.
Localisation
Oral mucosae and entire skin surface, especially head, neck and trunk.
Classification
- Pemphigus vulgaris: target antigens desmoglein 3 and desmoglein 1, suprabasal blister formation. Rare variants include neonatal pemphigus, pemphigus vegetans.
- Pemphigus foliaceus: target antigen desmoglein 1, subcorneal blister formation.
- Fogo selvagem (Brazilian pemphigus): endemic form of pemphigus foliaceus in Brazil, black flies (Simulium) may be vectors.
- Pemphigus erythematosus: pemphigus foliaceus with positive ANA and photosensitivity.
- Paraneoplastic pemphigus: autoantibodies against both intraepidermal and subepidermal attachment proteins. Intraepidermal and subepidermal blister formation.
- IgA pemphigus.
- Pemphigus herpetiformis.
Laboratory & other workups
Direct immunofluorescence (DIF): identification of in vivo bound intraepidermal, intercellular autoantibodies in the skin biopsy. Indirect immunofluorescence (IIF): identification in patient's serum of circulating autoantibodies against stratified squamous epithelium. ELISA for detection of anti-desmoglein 1 and 3 an autoantibodies in serum.
Dermatopathology
Intraepidermal clefts secondary to acantholysis.
Course
Chronic, progressive. If untreated may be fatal.
Complications
Before the introduction of systemic corticosteroids, high mortality rate (skin-related sepsis, marasmus secondary to fluid and protein loss, difficulty in eating). Today complications secondary to high-dose corticosteroids and other immunosuppressive therapy.
Diagnosis
Tzanck test: direct identification of acantholytic cells in smear of blister content (smear, Giemsa stain). Histology (acantholysis). DIF: intraepidermal intercellular IgG deposits. IIF: circulating IgG, which binds to stratified squamous epithelium in intercellular pattern. Immunoblot/ELISA: antibodies anti-desmoglein 1 and 3 autoantibodies in serum.
Differential diagnosis
- Mucosal and erosive oral lesions: acute herpetic stomatitis, aphthous stomatitis, erosive lichen planus, erythema multiforme major/Stevens-Johnson syndrome.
- Skin lesions: other autoimmune bullous diseases, erythema multiforme, Hailey-Hailey disease, staphylococcal scalded skin syndrome (SSSS), toxic epidermal necrolysis (TEN).
Prevention & Therapy
Systemic: rituximab, long-term immunosuppressive therapy (corticosteroids, azathioprine, methotrexate, dapsone, cyclophosphamide). In refractory cases: High dose intravenous immunoglobulins. Topical: general wound care.
Differential Diagnosis
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Tests
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