Pemphigus-Like Lesions in Sarcoidosis
Pemphigus-like lesions do not occur in sarcoidosis; these are distinct, unrelated diseases with completely different pathophysiology and clinical presentations that should not be confused.
Why These Are Separate Entities
Sarcoidosis produces granulomatous skin lesions, not pemphigus-like blistering. The cutaneous manifestations of sarcoidosis are fundamentally different from pemphigus:
Sarcoidosis Cutaneous Manifestations
- Specific (granulomatous) lesions include maculopapules, plaques, subcutaneous nodules, lupus pernio, and scar sarcoidosis—all characterized by non-caseating granulomas on histology 1, 2
- Non-specific lesions primarily consist of erythema nodosum, which appears as tender raised nodules on the shins 1, 3
- Cutaneous sarcoidosis presents as papules, plaques, nodules, or violaceous lesions—never as the flaccid bullae characteristic of pemphigus 1, 4
Pemphigus Pathophysiology
- Pemphigus is an autoimmune blistering disorder caused by antibodies against keratinocyte adhesion proteins (desmogleins), leading to intraepidermal acantholysis and flaccid bullae 1
- The Nikolsky sign in pemphigus reflects loss of keratinocyte adhesion, whereas in sarcoidosis there is no such mechanism 1
Critical Diagnostic Distinction
The histopathology is completely different and diagnostic:
- Sarcoidosis biopsy: Non-caseating epithelioid cell granulomas with CD4+ T-cell infiltration 1, 5
- Pemphigus biopsy: Intraepidermal acantholysis with suprabasal clefting and positive direct immunofluorescence for IgG deposits 1
Common Pitfall to Avoid
Do not misdiagnose other blistering conditions as "pemphigus-like sarcoidosis." If a patient with known sarcoidosis develops blistering lesions, consider:
- A separate, concurrent autoimmune blistering disease (pemphigus, pemphigoid, or other immunobullous disorders) 1
- Drug-induced blistering reactions from sarcoidosis treatments 1
- Infection or other unrelated dermatologic conditions
Any patient presenting with both granulomatous and blistering lesions requires separate biopsies of each lesion type with appropriate immunofluorescence studies to establish two distinct diagnoses 1, 5.