Cutaneous Signs in Dermatological Diseases; An Overview.

Cutaneous signs in dermatology are pathognomonic or diagnostic for certain conditions. A knowledge of these signs is a useful skill, which must not be forgotten in the recent trend towards relying on molecular biology and other investigative tools including histological findings to make a diagnosis. The aim of this review is to summarize all cutaneous signs in dermatology in a systematic way that would benefit dermatologists, trainee or experienced, in identifying diseases and sharpening their clinical skills. A keyword search for the terms "cutaneous signs," "sign" AND "dermatology" was conducted through PUBMED, Google, and the major textbooks in dermatology (i.e., Rooks Textbook of Dermatology; Fitzpatrick's Dermatology in General Medicine and Dermatology). References were searched thoroughly for all cutaneous signs described. One hundred and nineteen signs were noted and summarized under the following categories: autoimmune, infective, inflammatory, neoplastic, genetic, trauma/miscellaneous. This review would serve as a good reference for those wanting to improve their clinical acumen in diagnosing dermatological disease. Copyright:

Introduction

Sound knowledge of cutaneous signs in dermatology can help one identify life-threatening infections, rapidly spreading tumors, and many serious systemic conditions in a timely manner, hence allowing the clinician to initiate early management. Cutaneous signs in dermatology are under-utilized despite their potential benefits mainly due to the tendency on depending more on investigating tools including histopathological confirmation of disease, which can be both time-consuming and costly, especially in low-resource settings.

The aim of this review is to summarize the well-known cutaneous signs in dermatology in addition to the new signs that have only been described in the last 10 years and can be classified as “new knowledge” for both the trainees and the experienced dermatologists. We grouped the signs according to their pathological basis to make it easier to remember them.

Methodology

A PUBMED and Google search was conducted on 19th October 2020 for the terms: “cutaneous signs,” “sign” and “dermatology,” which resulted 563 articles. We have included both recognized and new eponymous signs. Three hundred abstracts were reviewed for relevance to our topic. Furthermore, the primary author searched the index of major textbooks in dermatology for the term “sign” to ensure that all cutaneous signs are summarized. This article only focuses on cutaneous signs in clinical dermatology, and dermatoscopic and radiological signs were excluded. One hundred and nineteen signs were noted, and these have been summarized under the following categories: autoimmune [Table 1], infective [Table 2], inflammatory [Table 3], neoplastic [Table 4], genetic [Table 5] and miscellaneous/others [Table 6]. We have not included the skin manifestations of COVID-19 as they are quite heterogeneous and cannot be described with an eponymous term or an exanthem.

Table 1

Cutaneous signs in autoimmune conditions

Signs	Type	Conditions associated with this sign	Description
Asboe Hansens sign[1] (variation of Bulla spread sign)	Autoimmune	Pemphigus vulgaris, acute bullous lichen planus	Extension of a blister to adjacent unblistered skin when pressure is applied to a bulla from the top of the lesion.
Barnett’s sign[2]	Autoimmune	Scleroderma	Thickening of skin over platysma in the hyperextended neck
Bravermans sign[3]	Autoimmune	Collagen vascular disease	Fine telangiectasias around the nail
Butterfly rash[4]	Autoimmune, infection	Systemic lupus erythematosus, dermatomyositis, pellagra, rosacea, cellulitis, atopic dermatitis	Red or purple facial rash with a butterfly pattern, affecting central face and usually sparing the nasolabial folds.
Cluster of jewels sign[5]	Autoimmune	Linear IgA bullous disease	Groups of small round or oval blisters filled with clear fluid
Corn flake sign[6]	Autoimmune, genetic	Kyrle’s and Flegel’s diseases	Papules with a characteristic irregular margin (corn flake sign) and underlying erythematous base, which tend to occur over lower extremities
Coudability sign[1]	Autoimmune, genetic	Alopecia areata	Normal-looking hairs tapered at the proximal end in the perilesional hair-bearing scalp and can easily be made to kink when bent or pushed inward.
Doughnut sign[6]	Autoimmune	Sclero myxedema	Induration of skin with central depression over proximal interphalangeal joint
Exclamation mark sign[7]	Autoimmune	Alopecia areata	Short broken off hairs that are narrower closer to the scalp and therefore mimic an exclamation mark without dot.
Filipovitch-Skibnevski sign (aka Heliotrope sign)[3]	Autoimmune	Dermatomyositis	Violaceous erythema involving the periorbital skin
Friar Tuck’s sign[1]	Autoimmune	Trichotillomania	Tonsure pattern
Franks’ sign[8]	Autoimmune	Coronary artery disease and/or Type 2 diabetes mellitus	Diagonal groove across the ear lobe in adults.
Gottron’s sign[9]	Autoimmune	Dermatomyositis	Scaly erythematous eruption seen on the dorsa of hands, the palms, axillae, and cubital fossae metacarpophalangeal joints, and proximal interphalangeal joints
Heliotrope sign[10]	Autoimmune	Dermatomyositis	Peri orbital violaceous hue
Holster sign[9]	Autoimmune	Dermatomyositis	Confluent macular violaceous erythema present on the lateral side of the hip and thighs
Ingram’s sign[1]	Autoimmune	Systemic sclerosis	Inability to retract the lower eye-lid
Jellinek’s sign[1]	Autoimmune	Hyperthryoridism	Eyelid hyperpigmentation, which can affect other areas of the face but spares the buccaneers mucosa.
Kaposi-Stemmer sign[11]	Autoimmune, infective, inflammatory	Chronic lymphedema	Inability to pinch or pick up a fold of skin at the base of the second toe
Mizutani’s sign (aka round finger pad sign)[1]	Autoimmune	Systemic sclerosis	Disappearance of the peaked contour on finger pads and replacement with a hemisphere-like fingertip contour, especially on ring fingers
Muehrcke’s sign[12]	Autoimmune, inflammatory	Nephrotic syndrome, glomerulonephritis, liver disease	Paired, transverse, narrowed white bands that run parallel to the lunula of the nails and are seen in patients with hypoalbuminemia
Oil drop sign[13]	Autoimmune	Psoriasis	Yellow-red discoloration and circular areas of onycholysis in the nail bed that fail to reach the free border and look like oil drops underneath the nail.
Nikolsky’s sign[14]	Autoimmune, infective	Pemphigus vulgaris, pemphigus foliaceus, staphylococcus skin scalded syndrome	Marginal/Indirect Nikolsky sign refers to the ability to split the epidermis of the skin beyond the preexisting erosion by pulling the remnant of a ruptured blister or rubbing at the periphery of existing lesions. Direct Nikolsk’y sign refers to the ability to split the epidermis on skin areas distant from the lesions by lateral pressure with a finger
Papular and nodular mucinosis of Gold[15]	Autoimmune	Cutaneous lupus mucinosis, systemic lupus erythematosus	Papules, nodules, and plaques secondary to mucin deposition on the neck.
Prayer sign[16]	Autoimmune	Diabetic cheiroarthropathy	Prayer sign is said to be positive when patient is unable to bring both the palmar surface together completely, and it indicates limited joint mobility.
Premalatha sign[17]	Autoimmune	Pemphigus vegetans	Cerebriform tongue
Punshi’s sign[1]	Autoimmune	Vitiligo	In women who suffer from vitiligo, white color of vitiligo macules turns to red-pink during menstruation and after the menstruation, it turns to the original color.
Racoon sign[18]	Autoimmune	Neonatal lupus erythematosis, primary systemic sclerosis, sweet syndrome associated with hematological malignancies	Erythematous, slightly scaly eruption on the face and periorbital skin.
Samitz’s sign[19]	Autoimmune	Dermatomyositis	Moth-eaten appearance of the cuticles
Shawl sign[14]	Autoimmune	Dermatomyositis	Confluent, symmetric, macular violaceous erythema on the posterior shoulders and neck, giving a distinctive shawl-like appearance.
Shuster’s sign[20]	Autoimmune	Discoid lupus erythematosus	Scarring of the concha.
Wickham’s striae[12]	Autoimmune	Lichen planus	Fine white lines on the surface of papules or plaques of lichen planus.
Stafne’s sign[1]	Autoimmune	Progressive systemic sclerosis	Widening of the periodontal ligament space .
V sign[12]	Autoimmune	Dermatomyositis	Confluent macular violaceous erythema on the anterior neck and chest.

Table 2

Cutaneous signs in infectious diseases

Signs	Type	Conditions associated with this sign	Description
Aldrich-Mees’ lines[21]	Infection, neoplasms, drugs, poisons	Severe infection, renal disease, cardiac disease, malignant disease, poisoning (arsenic, thallium)	Transverse white lines of discoloration across nails of fingers and toes, also known as leukonychia striata.
Beau’s lines[14]	Infection, idiopathic	Measles, mumps, coronary thrombosis, Kawasaki’s disease, pneumonia, pulmonary embolism, and renal failure.	Transverse depressions in the nail plate that occur after a stressful event that causes temporary cessation of the proliferation of proximal nail matrix.
Berliner sign[6]	Infection	Roseola infantum	Eyelid edema in a child giving clinical look of heavy eyelids or a “droopy” or “sleepy” appearance.
Blueberry muffin lesions[22]	Infection	Congenital cytomegalovirus infection	Infant presents with purple or red papules or nodules lasting for 4-6 weeks.
Borsari’s sign[3]	Infection	Scarlet fever	Pressure by a sharp object (such as a fingernail) producing a white line on the skin that quickly turns red.
Breakfast, lunch, and dinner sign[1]	Infection	Bed bugs bites	The bites of bed bugs (Cimex lectularius) usually follow a linear pathway in a group of three to five blood meals and are often referred to as “breakfast, lunch, and dinner.”
Bucket handle sign[6]	Infection	Syphilis	A fracture occurring through the degenerating metaphysis leading to exuberant callus formation resulting in a cap over the metaphysis is called “Bucket handle sign.”
Buschke-Ollendorff sign[1]	Infection, inflammation	Secondary syphilis and cutaneous vasculitis	Deep dermal tenderness on pressing the lesion (e.g., papular lesions of syphilis) with a pinhead.
Butterfly rash[14]	Infection, autoimmune	Cellulitis, systemic lupus erythematous, dermatomyositis, pellagra, rosacea, atopic dermatitis	Red or purple facial rash with a butterfly pattern, affecting the central face and usually sparing the nasolabial folds.
Chagas-Mazza-Romaña’s sign[1]	Infection	Chagas’ disease (American trypanosomiasis)	Palpebral unilateral induration of the eyelid.
Dory-flop sign[1]	Infection	Syphilis	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.
Du Bois sign[6]	Infection	Congenital syphilis	Shortening of the little finger.
Forchheimer’s sign[1]	Infection	Rubella	Red macules or petechiae on the soft palate.
Groove sign[1]	Infection, inflammation	Lymphogranuloma venereum, Eosinophilic fasciitis	Inflammatory mass of femoral and inguinal nodes separated by a depression or groove made by Poupart’s (inguinal) ligament. This sign can also be used to describe eosinophilic fasciitis (Shulman’s syndrome) where there is linear groove or indentation along the superficial veins of the medial aspect of the upper extremity.
Hang-glider sign[1]	Infection	Scabies	Dark triangular biting apparatus of Sarcoptes scabiei seen at the end of the subcorneal tunnel.
Hanging curtain sign[23]	Infection	Pityriasis Rosea	When the skin is stretched across the long axis of the herald patch, the scale is noted to be finer, lighter, and attached at one end, which tends to fold across the line of stretch.
Hertoghe’s sign[1]	Infection, autoimmune, inflammatory	Leprosy, systemic sclerosis, myxedema, follicular mucinosis, atopic dermatitis, trichotillomania, ectodermal dysplasia, discoid lupus erythematosus, alopecia areata, syphilis, ulerythema ophryogenes, HIV infection, and hypothyroidism	Loss of lateral one third of eye-brows.
Higoumenaki’s sign[24]	Infection	Congenital syphilis	Enlargement of the sternal end of the clavicle.
Hoagland’s sign[25]	Infection	Infective mononucleosis	Transient eyelid edema
Huthchinson sign[26]	Infection	Herpes zoster virus	Suspected herpes zoster blister/rash on the tip and side of the nose, which is a strong predictor of ocular involvement.
Hypopyon sign[27]	Infection	Pyoderma, infected vesiculobullous disease, subcorneal pustural dermatosis	Small, discrete, vesicles either flaccid or tense that become secondarily infected and pus accumulates in the lower half of the pustule.
Janeway lesion[14]	Infection	Bacterial endocarditis	Non tender and hemorrhagic lesions seen on the palms and the soles.
Knife-cut sign[28]	Infection	Herpes simplex virus, Crohn’s disease	Linear ulcers and fissures in intertriginous areas, such as the folds in the inguinal area, the vulva, and the abdomen.
Koplik’s spots[14]	Infection	Measles	Clustered white lesions on buccal mucosa that appear a few days before the measles rash itself.
Osler’s nodes[14]	Infection	Bacterial endocarditis	Painful erythematous nodules on the pads of fingers and toes.
Pitaluga’s sign[1]	Infection	Cutaneous leishmaniasis	Acquired hypertrichosis of eyelashes.
Romana’s sign[29]	Infection	Trypanosoma cruzi	Severe unilateral conjunctivitis and palpable, painless lid edema.
Scratch sign (coup d’ongle sign, Besnier’s sign, stroke of the nail)[1]	Infection	Pityrysis vesicolor	Pityrysis scales are made to stand out by scratching the lesion with fingernail.
Slapped cheek sign[14]	Infection	Fifth disease (parvovirus B 19)	Confluent, erythematous, edematous plaques on the face.
Tap sign[30]	Infection	Leprosy	Deep pain upon percussion of lesions over bone in tuberculoid leprosy and borderline tuberculoid leprosy, in spite of superficial sensory impairment.
Thumbprint sign[6]	Infection	Disseminated strongyloidiasis	Periumbilical purpura resembling thumbprints.
Turkey ear sign[31]	Infection	Lupus vulgaris, sarcoidosis, leprosy, leishmaniasis	Massively enlarged earlobe with bluish-red or violaceous indurated plaques and nodules.
Volcano sign[1]	Infection	Cutaneous leishmaniasis	Small nontender papule, which enlarges in size and ulcerates in the center.
Wartenberg’s sign[32]	Infection	Leprosy	Little finger assumes the position of constant abduction (ulnar nerve paralysis).
Winterbottom’s sign[33]	Infection	African trypnosomiasis	Enlargement of the lymph nodes in the posterior cervical group.

Table 3

Cutaneous signs in inflammatory conditions

Signs	Type	Conditions associated with this sign	Description
Auspitz sign [Figure 1][14]	Inflammatory	Psoriasis	Pin point bleeding after scraping to remove scales in psoriasis.
Butterfly sign[14]	Inflammatory	Neurodermatitis/lichen simplex chronicus, prurigo nodularis	Sparing of the mid scapular region in patients having prurigo nodularis, lichen simplex chronicus as they are unable to reach the region for scratching.
Coral bead sign[1]	Inflammatory	Multicentric reticulohistiocytosis	Nail fold xanthomas
Caput medusae[34]	Inflammatory, infective	Portal Venous HTN, liver failure	Dilated abdominal vein vessels radiating from the umbilicus.
Carpet tack sign[1]	Inflammatory	Discoid lupus erythematosus	On removal of an adherent scale of DLE, the undersurface shows horny protuberant plugs that had occupied patulous hair follicles.
Darier’s sign[35]	Inflammatory, neoplastic	Mastocytosis, urticaria pigmentosa	Urtication, flare, swelling, and blister formation due to the release of histamine from rubbing a flare of mastocytosis
Deck chair sign[36]	Inflammatory	Ofuji populous-erythroderma	Peculiar erythroderma with selective sparing of skin folds (axillar, inguinal, sub mammary) and flexures.
Dennie-Morgan fold[37]	Inflammatory	Atopy	Extra fold of skin beneath the eye.
Dimple sign[1]	Inflammatory, neoplastic	Dermatofibroma	Squeezing the skin adjacent to a dermatofibroma causes a dimpled appearance on its surface.
Dirty neck sign[38]	Inflammatory	Atopic Dermatitis	Hyperpigmentation of the neck.
Groove sign[1]	Infection, inflammation	Lymphogranuloma venereum, Eosinophilic fasciitis	Inflammatory mass of femoral and inguinal nodes separated by a depression or groove made by Poupart’s (inguinal) ligament. This sign can also be used to describe eosinophilic fasciitis (Shulman’s syndrome) where there is linear groove or indentation along the superficial veins of the medial aspect of the upper extremity.
Hertoghe’s sign[1]	Inflammatory, Infection, autoimmune,	Atopic dermatitis, leprosy, systemic sclerosis, myxedema, follicular mucinosis, trichotillomania, ectodermal dysplasia, discoid lupus erythematosus, alopecia areata, syphilis, ulerythema ophryogenes, HIV infection, and hypothyroidism.	Loss of lateral one third of eye-brows.
Kaposi-Stemmer sign[11]	Inflammatory, autoimmune, infective	Chronic lymphedema	Inability to pinch or pick up a fold of skin at the base of the second toe.
Knife-cut sign[28]	Inflammatory, infective	Herpes Simplex Virus, Crohn’s disease	Linear ulcers and fissures in intertriginous areas, such as the folds in the inguinal area, vulva, and abdomen.
Koebner’s phenomenon[14]	Inflammatory	Psoriasis, vitiligo, lichen planus	Appearance of new skin lesions on areas of cutaneous injury in otherwise healthy skin.
Meffert’s sign[1]	Inflammatory	Fordyce’s	Presence of ectopically located sebaceous glands on the lips, oral mucosa, and less commonly on gums.
Milian’s ear sign[1]	Inflammatory, infective	Erysipelas	It is a sign used to distinguish between erysipelas and cellulitis of the facial region, where there is involvement of the ear in erysipelas and sparing in cellulitis.
Muehrcke’s sign[12]	Inflammatory, autoimmune	Nephrotic syndrome, glomerulonephritis, liver disease.	Paired, transverse, narrowed white bands that run parallel to the lunula of the nails and are seen in patients with hypoalbuminemia.
Nose sign (Pavithran’s nose sign)[39]	Inflammatory	Severe atopic dermatitis, airborne contact dermatitis, exfoliative dermatitis,	Sparing of the nose and peri-nasal areas in exfoliative dermatitis.
Pathergy sign[14]	Inflammatory	Pyoderma gangrenosum or Behcet’s disease	Appearance of a new lesion or worsening of the existing lesions by superficial trauma.
Pup-tent sign[1]	Inflammatory	Lichen planus	Nail splits and elevates longitudinally with downward angle of lateral nail edge.
Walzel sign[6]	Inflammatory	Pancreatitis	Mottled reticulated vascular pattern that appears as a lace-like purplish discoloration of the skin (livedo reticularis).
Rope sign[1]	Inflammatory	Interstitial granulomatous dermatitis with arthritis	Thick indurated inflammatory cord- like structure on the skin that extends from the lateral trunk to the axillae.

Table 4

Cutaneous signs in neoplastic disease

Signs	Type	Conditions associated with this sign	Description
Aldrich-Mees’ lines[21]	Neoplastic, infection, and drugs.	Malignant disease poisoning (arsenic, thallium), severe infection, renal disease, cardiac disease	Transverse white lines of discoloration across nails of fingers and toes, also known as leukonychia striata
Brenner’s sign[40]	Neoplastic	Melanoma	Erythematous eruption surrounding a melanoma.
Clown nose sign[4142]	Neoplastic	Squamous cell carcinoma	Nodular metastatic lesion on the nasal tip.
Darier’s sign[14]	Neoplastic, inflammatory	Mastocytosis, urticaria pigmentosa	Urtication, flare, swelling and blister formation due to release of histamine from rubbing a flare of mastocytoma.
Dimple sign[43]	Neoplastic, inflammatory	Dermatofibroma	Squeezing the skin adjacent to a dermatofibroma causes a dimpled appearance on its surface.
Hildreth’s sign[44]	Neoplastic	Glomus tumor	Relied of pain and tenderness on exsanguination and ischemia of the affected part by raising the extremity affected and inflating a sphygmomanometer applied to it above the systolic blood pressure, and sudden return of pain when pressure on the cuff is relieved.
Hutchinson’s nail sign[14]	Neoplastic	Subungual melanoma	Periungual extension of brown-black pigmentation onto the proximal and/or lateral nail folds.
Kerr’s sign[3]	Neoplastic	Spinal cord lesion	A palpable change in skin texture (stiff, dry, or tense) inferior to the somatic level of a spinal cord lesion
Leser-Tre’lat sign[45]	Neoplastic	Adenocarcinomas, lung cancer, melanoma, mycoses fungoids	Sudden eruption of numerous seborrheic keratosis, usually associated with pruritus.
Love’s sign[1]	Neoplastic	Glomus tumor	Exact localization of tenderness with the help of pin head in glomus tumor.
Marjolin’s ulcer[46]	Neoplastic	Venous ulcers, chronic pressure sores, burn scars	Malignant transformation within a burnt scar but can also be seen in chronic pressure sores, venous ulcers
Nazzaro’s sign[1]	Neoplastic	Multiple Myeloma	Follicular hairy hyperkeratosis, especially on the face.
Sister Mary Joseph’s nodule[47]	Neoplastic	Metastatic, usually intra-abdominal, malignant disease such as primary malignancy of stomach, bowel, and/or pancreas.	Firm, indurated nodules, sometimes with fissuring or ulceration of the umbilicus.
Tent sign[6]	Neoplastic	Pilomatricoma	A solitary, asymptomatic, firm nodule. When the overlying skin is stretched, the lesion appears to be multifaceted and angulated, giving a ‘‘tent’’ appearance.
Tripe palms sign[48]	Neoplastic	Internal malignancy, acanthosis nigricans	The rugose thickening of the palmar surface of the hands
Ugly duckling sign[49]	Neoplastic	Melanoma	Naevus that does not resemble other nevi is more likely to be suspicious of melanoma.

Table 5

Cutaneous signs in genetic conditions

Sign	Type	Conditions associated with the sign	Description
Albright dimpling sign[1]	Genetic	Albright’s hereditary osteodystrophy	Short metacarpals and dimpling of the knuckles.
Antenna sign[1]	Genetic	Keratosis pilaris	Individual hair follicles show a long strand of keratin glinting when examined in tangentially incident light.
Buttonhole sign[1]	Genetic	Anetoderma, type 1 Neurofibromas	Lesion can be invaginated with the tip of index finger back into the subcutis and again reappear after release of pressure.
Corn flake sign[6]	Genetic, autoimmune	Kyrle’s and Flegel’s diseases	Papules with a characteristic irregular margin (corn flake sign) and underlying erythematous base, which tend to occur over lower extremities.
Coudability sign[50]	Genetic, autoimmune	Alopecia areata	Normal-looking hairs tapered at the proximal end in the perilesional hair-bearing scalp and can easily be made to kink when bent or pushed inward.
Crowe’s sign[1]	Genetic	Neurofibramatosis 1	Axillary freckling
Gorlin’s sign[51]	Genetic	Ehlers Danlos syndrome	Ability to touch the tip of the nose with the extended tongue.
Hair collar sign[14]	Genetic	Cranial dysraphism	Smooth dome-shaped hairless nodules and sometimes a collar of hypertrichosis surrounds them.
Osler’s sign[1]	Genetic	Alkaptonuria	Blue black pigmentation in the sclera near insertion of rectus muscle.
Patrick Yesudian sign[1]	Genetic	Type 1 neurofibramatosis	Palmar melanotic macules (palmar freckling).
Reticulate acropigmentation of Dohi[52]	Genetic	Dyschromatosis symmetrica hereditaria	Appear in infancy or early childhood as pinpoint to pea-sized flat (macular) spots of increased and decreased pigmentation on the back of the hands.
Reverse namaskar sign[1]	Genetic	Eahlers Danlos syndrome	Ability to fold ones forearms at the back and oppose their palms to say “Namaskar.”
Sternberg’s thumb sign[1]	Genetic	Marfan’s syndrome	The thumbs protrude from the clenched fist beyond the ulnar border of hand, also associated with psoriasis.
Walker- Murdoch’s/Wrist sign[1]	Genetic	Marfan’s syndrome	The distal phalanx of the first and fifth fingers of the hand overlaps when wrapped around the opposite wrist

Table 6

Miscellaneous/other cutaneous signs in dermatology

Signs	Type	Conditions associated with this sign	Description
Alcohol wipe sign[53]	Miscellaneous	Terra firma-forme dermatosis	Reticulated brown patches that are dirt-like and can be cleared by forceful rubbing with alcohol wipes.
Ball-SITE sign[54]	Trauma	Cutaneous injury from a high-velocity ball (i.e., paint ball; ping pong ball)	Sports-induced targetoid erythema (annular red ring surrounding a central area of normal appearing skin).
Beau’s lines[24]	Miscellaneous, infection	Any severe acute illness, coronary thrombosis, measles, mumps, Kawasaki’s disease, pneumonia, pulmonary embolism, and renal failure.	Transverse depressions in the nail plate that occur after a stressful event that causes temporary cessation of the proliferation of proximal nail matrix.
Blue dot sign[55]	Trauma	Testicular torsion	A blue or black nodule is visible under the skin on the superior aspect of the testis or epididymis.
Cullen’s sign[1]	Trauma	Acute hemorrhagic pancreatitis and ruptured ectopic pregnancy	Periumbilical ecchymosis
Drip sign[6]	Miscellaneous	Dermatitis artefacta	Patterned burned areas corresponding to the areas of dripping of the corrosive liquid.
Ear lobe sign[56]	Miscellaneous	Facial contact dermatitis	Contact dermatitis to a substance applied with one hand to the skin of the face and neck. On the ipsilateral side of the face, the ear-lobe is spared, whereas on the contralateral side, the ear-lobe is involved.
Enamel paint sign[57]	Miscellaneous	Kwashiorkor	Sharply demarcated hyperpigmented desquamating patches and plaques resembling enamel paint.
Flag sign[1]	Miscellaneous	Marasmus, Kwashiorkor	Presence of sharply demarcated alternating bands of normally pigmented and hypopigmented zone of hair indicating episodes of normal nutrition and intermittent malnutrition respectively, seen in kwashiorkor- or marasmus-type malnutrition
Necklace of Casal sign[58]	Miscellaneous	Pellagra	Hyperpigmentation in the neck area
Panda’s sign[6]	Miscellaneous	Post laser therapy for naevus of Ota	Persistence of naevus of Ota in the periorbital location following laser therapy, whereas peripheral sites clear well.
Russell’s sign[59]	Miscellaneous	Bulimia	Crusted callous on the knuckles of the dominant hand.
School chair sign[60]	Miscellaneous	Allergic contact dermatitis to nickel	Rash on the posterior thighs corresponding to contact with a school chair.
Grey Turner’s sign[61]	Trauma	Acute hemorrhagic pancreatitis and retroperitoneal hemorrhage	Induration and bruising seen on the skin over the costo-vertebral angle secondary to the spread of blood from the anterior peri-renal space.

Auspitz sign: Pin-point bleeding seen when the scale is removed from a psoriatic plaque.[14] Source: Original patient

Interestingly, the original descriptions for these signs are based on the cultural connotations of colors, flora, fauna, and other structures that the describing clinician is familiar with. Some of the signs are self-explanatory by morphology or method of eliciting, but several signs with the name of the scientist emphasize the recognition given to the person who described it first. An exhaustive description of all signs described in dermatology is beyond the scope of this article. However, we describe all the important and lifesaving signs and present the important dermatological signs under different disease categories in alphabetical order for easy reference.

Conclusion

With recent technological advancements in tissue diagnosis, many clinicians have become accustomed to the investigation-based diagnosis of diseases and less confident in recognizing clinical signs that can guide the initial diagnosis and expedite management. This article was developed with the purpose of providing the busy clinician with a quick reference for identifying various cutaneous signs and their association with various medical conditions.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.62