Nikolsky Sign
The Nikolsky sign is a crucial clinical maneuver used to assess the integrity of the epidermis. It is considered positive when slight lateral pressure on the skin (or near a bulla) causes the epidermis to detach or slide off, resulting in an erosion.
Clinical Significance
| Disease | Nikolsky Result | Reasoning |
|---|---|---|
| Pemphigus Vulgaris | Positive | Loss of intercellular adhesions (desmosomes). |
| SJS / TEN | Positive | Full-thickness epidermal necrosis. |
| Bullous Pemphigoid | Negative | Dermo-epidermal junction remains intact. |
Key Considerations
- Method: Gently rub non-involved, perilesional skin. If it slides away, it is positive.
- Caution: Perform this test gently to avoid causing unnecessary pain or excessive erosion in an already compromised patient.
High-Yield Exam Pearl:
- SJS/TEN vs. Pemphigus: While both show a positive Nikolsky, SJS/TEN typically presents with widespread, “sheet-like” loss and is associated with severe mucosal involvement and drug triggers. Pemphigus Vulgaris is an autoimmune blistering disease with chronic, progressive bullae.