Pathophysiology of pemphigus vulgaris
1) pemphigus vulgaris is an autoimmune bullous skin disease resulting from formation of a pemphigus antibody against desmoglein 1 an 3 molecules (component of desmosomes located between keratinocytes)
2) type 2 hypersensitivity reaction
Signs and Symptoms
1) flaccid blisters in mouth, face, scalp, neck, axilla, and torso
2) itching and pain at site of lesions
3) skin becomes denuded
4) posthealing hyperpigmentation
5) blisters can ulcerate and become secondarily infected
6) severe cachexia
7) positive Nikolsky’s sign
Characteristic Test Findings
IgG autoantibodies against epithelial cell desmogleins (1 and 3)
Histology and Gross Pathology
1) epidermal cells lose cohesion (acantholysis) with formation of intraepidermal blisters
2) intact basal cells form blister base
Associated Conditions
1) increased incidence in HLA-DR4 and HLA-DRw6
2) lesions can also occur in esophagus, pharynx, larynx, conjunctiva, rectum, and vagina
Inheritance/Epidemiology
occurs mostly in elderly patients
Treatment
1) glucocorticoids (usually prednisone)
2) azathioprine or cyclophosphamide
Tips for USMLE
1) Nikolsky’s sign is separation of epidermis when skin is manually pressed
2) if there are no mouth lesions, it is not pemphigus vulgaris
3) if question mentions denuded skin and flaccid blisters, think pemphigus vulgaris
4) if question mentions intraepidermal blisters, think pemphigus vulgaris
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