- Clinical science
Autoimmune blistering diseases are skin conditions characterized by the formation of blisters, which are the result of the destruction of cellular or extracellular adhesion molecules by antibodies. The three most significant autoimmune blistering diseases are bullous pemphigoid, pemphigus vulgaris, and dermatitis herpetiformis. The most common among these is bullous pemphigoid, which leads to the formation of large, tense bullae. It is a chronic disease that mainly affects elderly individuals and responds well to treatment with steroids. Pemphigus vulgaris, which is characterized by fragile, superficial flaccid bullae that leave crusted erosions, is a rare condition that occurs mainly in middle-aged adults. In contrast to bullous pemphigoid, it is a severe condition that is more difficult to treat and can be fatal. Dermatitis herpetiformis mainly affects the extensor surfaces of the extremities and is associated with celiac disease. It has a chronic course that leads to the formation of intensely pruritic papules and vesicles. In addition to evaluating clinical appearance, the Nikolsky sign, Tzanck test, skin biopsy, and direct immunofluorescence are indicated to confirm the diagnosis. Serologic testing of autoantibodies may also be useful. Management usually consists of oral and topical steroids, as well as immunosuppressive therapy.
|Bullous pemphigoid||Pemphigus vulgaris||Dermatitis herpetiformis|
|Epidemiology|| || |
|Clinical findings|| || |
|Diagnostics||Autoantibodies against|| |
|Tzanck test|| || || |
|Nikolsky's sign|| || || |
|Histology and immunohistochemistry|
|Prognosis|| || || |
Variant forms of bullous pemphigoid
- Definition: bullous, pemphigoid-like dermatosis during pregnancy of unknown cause (most likely immunological)
- Epidemiology: 1:50,000 pregnancies (in the US)
- Commonly starts in the periumbilical region during the 2nd and 3rd trimester
- Intensely pruritic, mostly non-blistering lesions (eczema, urticarial or papular lesions) on extremities and mucous membranes
- Grouped vesicles with herpetiform appearance (“gestational herpes”) usually occur as the disease advances.
- Diagnostics: The diagnosis is confirmed via biopsy and immunofluorescence.
- Usually self-limiting; heals spontaneously after delivery; , but associated with complications (e.g., premature labor; , increased lifetime risk of autoimmune disease)
Variant forms of pemphigus vulgaris
- Etiology: : autoimmune disease (only antibodies against desmoglein 1 detectable)
- Clinical presentation
In addition to evaluating clinical appearance, specific tests are performed to confirm the diagnosis of a blistering disease. For specific diagnostic findings, see .
- Slight mechanical pressure (by rubbing) is exerted on the skin → upper epidermal layer slips away from lower layer →separation of epidermis → blistering
- Test is positive on previously unaffected skin
- Nikolsky's sign is present in pemphigus vulgaris , toxic epidermal necrolysis, , scalding, bullous impetigo, and
- Not present in bullous pemphigoid
- Microscopic examination of scrapings from the base of a lesion to look for Tzanck cells
- Tzanck cells (multinucleated giant cells) are present in:
- No detection of Tzanck cells in:
- Skin biopsy
- Serum testing with indirect immunofluorescence (IDIF): Detection of circulating autoantibodies
- In addition in dermatitis herpetiformis: small intestine biopsy