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Related Subjects:
|Nikolsky's sign
|Koebner phenomenon
|Erythema Multiforme
|Pyoderma gangrenosum
|Erythema Nodosum
|Dermatitis Herpetiformis
|Lichen Planus
|Acanthosis Nigricans
|Acne Rosacea
|Acne Vulgaris
|Alopecia
|Vitiligo
|Urticaria
|Basal Cell Carcinoma
|Malignant Melanoma
|Squamous Cell Carcinoma
|Mycosis Fungoides (Sezary Syndrome)
|Xeroderma pigmentosum
|Bullous Pemphigoid
|Pemphigus Vulgaris
|Seborrheic Dermatitis
|Pityriasis/Tinea versicolor infections
|Pityriasis rosea
|Scabies
|Dermatomyositis
|Toxic Epidermal Necrolysis
|Stevens-Johnson Syndrome
|Atopic Eczema/Atopic Dermatitis
|Psoriasis
The false Nikolsky sign is elicited by pulling on the roof of a blister, causing extension of the lesion into surrounding skin.
It indicates blister fragility but not true acantholysis (the dermo-epidermal junction remains intact).
🧠 Teaching tip:
A “+ Nikolsky sign” means the epidermis is unstable and separates easily — a hallmark of intraepidermal blistering (e.g. pemphigus).
A “– Nikolsky sign” indicates subepidermal pathology (e.g. bullous pemphigoid).
Always think about the level of blister formation to understand the mechanism. ⚗️
🩺 What is Nikolsky’s Sign?
🔬 Pathophysiology
⚕️ Conditions with a Positive Nikolsky Sign
Condition
Mechanism
Key Feature
Pemphigus vulgaris / foliaceus
Autoantibodies to Desmoglein 1 and 3 → acantholysis
Flaccid bullae, mucosal involvement, intraepidermal split
Staphylococcal Scalded Skin Syndrome (SSSS)
Staph exfoliative toxin → Desmoglein 1 cleavage
Diffuse erythema and desquamation in infants/children
Toxic Epidermal Necrolysis (TEN)
Drug-induced keratinocyte apoptosis
Widespread epidermal necrosis, mucosal ulceration
❗ False Nikolsky Sign
💡 Clinical Importance
📚 References