Monday, 4 April 2016

Dermatology signs

Important Dermatology signs

[ 1] Nikolskiy- pemphigus, staphylococcal scalded skin syndrome, Toxic Epidermal necrolysis (pseudo-nikolskiy). Refers to easy peeling of skin on applying tangential pressure over a bony prominence on perilesional skin.

[2 ] Asboe-Hansen sign/Bulla spread sign : Enlargement of bulla by applying finger pressure to bulla in patients with pemphigus and bullous pemphigoid.

In pemphigus, blister extends angularly while in BP, it extends in oval fashion.

Extra edge fact: Rare causes of bulla spread sign are- other subepidermal blisters like dermatitis herpetiformis, epidermolysis bullosa acquisita, cicatricial pemphigoid, dystrophic epidermolysis bullosa. Also seen in drug reactions like Stevens-Johnson syndrome and toxic epidermal necrolysis.
Negative in SSSS and PF as in these disorders blisters are very fragile

[3 ] Auspitz sign: described in psoriasis, where there is pinpoint bleeding on removal of scales from the lesions of psoriasis.
The test by which Auspitz sign is elicited is called as Grattage test (scratching). It is attributed to parakeratosis, suprapapillary thinning of the stratum malphighii, elongation of dermal papillae and dilatation and tortuosity of the papillary capillaries. The thin membrane visible after removal of all scales from the lesion is called bulkeley membrane.  However, Auspitz sign is not sensitive or specific for psoriasis. It is not seen in inverse psoriasis; pustular, erythrodermic psoriasis; guttate psoriasis. Not specific because it is also seen in nonpsoriatic scaling disorders, including Darier's disease and actinic keratosis.

[ 4] Button  hole sign: In type 1 neurofibromatosis, neurofibromas can be invaginated with the tip of index finger back into the subcutis and again reappear after release of pressure. Other condition where one can find positive buttonhole sign is dermatofibroma.

[ 5] Carpet tac sign/ tin tack sign/ cats tongue sign: When the adherent scale is removed from the lesions of discoid lupus erythematosus, the undersurface of the scale shows horny plugs that have occupied dilated hair follicles. This sign is also seen in seborrheic dermatitis

[6 ] Darier's sign: Rubbing a lesion of mastocytoma causes urticaria, flare, swelling. In contrast, pseudo-Darer's sign is seen in smooth muscle hamartoma where there is increase in induration and piloerection after firm stroking. Other conditions where one could find positive Darier's sign are leukemia cutis, juvenile xanthogranuloma, and Langerhans cell histiocytosis.

[7 ] Dory Flop sign: It is described in relation to syphilitic chancre on the coronal border of the prepucial skin in an uncircumscribed male, whereupon on retracting the foreskin the entire ulcer flips out all at once because it is too hard to bend due to underlying button like induration.

[8 ] Groove sign: seen in lymphogranuloma venereum (LGV).  Enlargement of both inguinal and femoral group of lymph nodes separated by inguinal ligament produces a groove known as the "Groove sign of Greenblatt."

[9 ] Hanging curtain sign: It is seen in patients with pityriasis rosea. When the skin is stretched across the long axis of the herald patch, the scale is noted to be attached at one end and free at the other end, and stretches like hanging curtain

[ 10]  Scratch sign: In Pityriasis versicolor often the scale is not visible. An important diagnostic clue may be the loosing of barely perceptible scale with a fingernail, which is called as the scratch sign. This sign may be negative if patient has taken recent bath or in case of treated lesion, in which case, only hypopigmentation persists.

[11] Bushke-ollendorf sign/Deep dermal tenderness: This is a sign to be elicited in case of secondary syphilis and cutaneous vasculitis, where there is deep dermal tenderness on pressing the lesion (e.g., papular lesions of syphilis) with a pinhead

Compiled by Dr. Saurabh Jindal

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