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Skin & Nail Signs

Signs of the skin and nails: the rubbing and scratching tests of blistering and scaly diseases, the rashes of dermatomyositis, and the nail changes that mirror disease of the liver, kidneys and blood.

This page lists all 44 of them in the guide. Open any sign for how it is elicited, what it suggests, and its eponym story where it has one.

SignSystemA positive finding is associated with
Acanthosis nigricansSkin & NailsAssociated with insulin resistance and type 2 diabetes; rarely and when rapidly progressive in an older adult, it is associated with internal cancer.
Asboe-Hansen signSkin & NailsAssociated with blistering diseases where the skin splits easily, such as pemphigus vulgaris — an extension of the Nikolsky phenomenon.
Ash-leaf spotsSkin & NailsAssociated with tuberous sclerosis complex.
Auspitz's signSkin & NailsAssociated with psoriasis, because the thinned skin over the plaque exposes dilated capillaries.
Beau's linesSkin & NailsAssociated with a period when nail growth was interrupted — severe illness, high fever, chemotherapy or major stress.
Buttonhole signSkin & NailsAssociated with neurofibromas in neurofibromatosis type 1.
Café-au-lait spotsSkin & NailsMultiple large spots are associated with neurofibromatosis type 1.
Carpet tack signSkin & NailsAssociated with discoid lupus erythematosus, where scale is anchored in plugged hair follicles.
Crowe's signSkin & NailsAssociated with neurofibromatosis type 1.
Darier's signSkin & NailsAssociated with cutaneous mastocytosis (such as urticaria pigmentosa), where rubbing releases histamine from mast cells in the skin.
DermographismSkin & NailsAssociated with a common form of physical urticaria; a exaggerated version is found in a few percent of healthy people.
Erythema nodosumSkin & NailsAssociated with inflammation of the fat under the skin, triggered by infections (such as strep throat), sarcoidosis, inflammatory bowel disease, pregnancy or certain medicines.
Facial angiofibromasSkin & NailsAssociated with tuberous sclerosis complex.
Fitzpatrick's sign (dimple sign)Skin & NailsAssociated with dermatofibroma, a common benign skin growth.
Gottron's papulesSkin & NailsAssociated with dermatomyositis, an inflammatory disease of muscle and skin.
Heliotrope rashSkin & NailsAssociated with dermatomyositis.
Herald patchSkin & NailsAssociated with the start of pityriasis rosea.
Hutchinson's nail signSkin & NailsAssociated with subungual melanoma — a melanoma growing under the nail.
Hutchinson's sign (zoster)Skin & NailsAssociated with involvement of the nasociliary branch of the trigeminal nerve, which also supplies the eye — so eye involvement is more likely and needs eye assessment.
Koebner phenomenonSkin & NailsAssociated with psoriasis, lichen planus and vitiligo, among other skin diseases.
Leser–Trélat signSkin & NailsReported as associated with an internal cancer, especially of the stomach and gut, though the association is debated because both are common with age.
Livedo reticularisSkin & NailsMild forms are a normal response to cold; persistent forms are associated with vasculitis, antiphospholipid syndrome and cholesterol embolisation.
Mechanic's handsSkin & NailsAssociated with the antisynthetase syndrome, a form of inflammatory muscle disease with lung involvement.
Mees' linesSkin & NailsAssociated with arsenic poisoning, and also with chemotherapy and severe systemic illness.
Muehrcke's linesSkin & NailsAssociated with very low blood albumin, as in nephrotic syndrome and severe malnutrition.
Nail pittingSkin & NailsAssociated with psoriasis, and also with alopecia areata and eczema.
Necrobiosis lipoidicaSkin & NailsAssociated with diabetes mellitus, most often type 1, though it can occur without diabetes.
Nikolsky's signSkin & NailsAssociated with skin fragility in blistering diseases such as pemphigus vulgaris and toxic epidermal necrolysis.
OnycholysisSkin & NailsAssociated with psoriasis, fungal nail infection, thyroid disease and some medicines and chemicals.
Palmar erythemaSkin & NailsAssociated with liver disease, pregnancy, an overactive thyroid and rheumatoid arthritis, among other causes.
PathergySkin & NailsAssociated with Behçet's disease, and also seen in pyoderma gangrenosum and Sweet syndrome.
Periungual telangiectasiaSkin & NailsAssociated with connective tissue diseases, especially dermatomyositis and systemic sclerosis.
Pretibial myxoedemaSkin & NailsAssociated with Graves' disease (autoimmune thyroid disease), usually alongside thyroid eye disease.
Raynaud's phenomenonSkin & NailsPrimary Raynaud's is common and benign; secondary Raynaud's is associated with connective tissue diseases such as systemic sclerosis, and with vibration injury.
Scabies burrowsSkin & NailsAssociated with scabies infestation; intense itching, worst at night, is the usual companion symptom.
SclerodactylySkin & NailsAssociated with systemic sclerosis (scleroderma).
Shagreen patchSkin & NailsAssociated with tuberous sclerosis complex.
Shawl signSkin & NailsAssociated with dermatomyositis.
Spider naeviSkin & NailsA few can be normal, especially in children and pregnancy; many are associated with liver disease and raised oestrogen levels.
Target lesionsSkin & NailsAssociated with erythema multiforme, usually triggered by infections (especially herpes simplex) or medicines.
Terry's nailsSkin & NailsAssociated with cirrhosis of the liver, and also with heart failure, diabetes and malnutrition.
Uraemic frostSkin & NailsAssociated with advanced, untreated kidney failure (uraemia); now rare where dialysis is available.
Wickham's striaeSkin & NailsAssociated with lichen planus.
XanthelasmaSkin & NailsAssociated with raised blood lipids in about half of cases; the other half have normal lipids, and the plaques are also a marker of cardiovascular risk.
Please note: This page is an educational reference about clinical examination signs. A clinical sign supports — and never replaces — a full clinical evaluation, examination and appropriate testing. A sign being present does not by itself prove a diagnosis, and an absent sign does not rule one out. If you have symptoms that worry you, see a health professional.