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Description of Skin Lesions

By

Julia Benedetti

, MD, Harvard Medical School

Reviewed/Revised Jan 2024
View PATIENT EDUCATION
Topic Resources

An extensive language has been developed to standardize the description of skin lesions, including

Rash is a general term for a temporary skin eruption.

Cross-Section of the Skin and Skin Structures

Cross-Section of the Skin and Skin Structures

Lesion Type (Primary Morphology)

Macules are flat, nonpalpable lesions usually < 10 mm in diameter. Macules represent a change in color and are not raised or depressed compared to the skin surface. A patch is a large macule. Examples include freckles, flat moles, tattoos, and port-wine stains Capillary Malformations Capillary Malformations , and the rashes of rickettsial infections Overview of Rickettsial and Related Infections Overview of Rickettsial and Related Infections , rubella Rubella Rubella , measles Measles Measles (can also have papules and plaques), and some allergic drug eruptions Drug Eruptions and Reactions Drug Eruptions and Reactions .

Papules are elevated lesions usually < 10 mm in diameter that can be felt or palpated. Examples include nevi Moles Moles , warts Warts Warts , lichen planus Lichen Planus Lichen Planus , insect bites, seborrheic keratoses Seborrheic Keratoses Seborrheic Keratoses , actinic keratoses Actinic keratoses Chronic affects of sunlight include photoaging, actinic keratoses, and skin cancer. (See also Overview of Effects of Sunlight.) Chronic exposure to sunlight ages the skin (photoaging, dermatoheliosis... read more Actinic keratoses , some lesions of acne Acne Vulgaris Acne Vulgaris , and skin cancers Overview of Skin Cancer . The term maculopapular is often loosely and improperly used to describe many erythematous rashes; because this term is nonspecific and easily misused, it should be avoided.

Plaques are palpable lesions > 10 mm in diameter that are elevated or depressed compared to the skin surface. Plaques may be flat topped or rounded. Lesions of psoriasis Psoriasis Psoriasis and granuloma annulare Granuloma Annulare Granuloma Annulare commonly form plaques.

Nodules are firm papules or lesions that extend into the dermis or subcutaneous tissue. Examples include cysts Cutaneous Cysts Cutaneous Cysts , lipomas Lipomas Lipomas , and fibromas Dermatofibromas Dermatofibromas .

Pustules are vesicles that contain pus. Pustules are common in bacterial infections and folliculitis and may arise in some inflammatory disorders including pustular psoriasis Subtypes of Psoriasis Subtypes of Psoriasis .

Urticaria Urticaria Urticaria (wheals or hives) is characterized by elevated lesions caused by localized edema. Wheals are pruritic and erythematous. Wheals are a common manifestation of hypersensitivity to medications, stings or bites, autoimmunity, and, less commonly, physical stimuli including temperature, pressure, and sunlight. The typical wheal lasts < 24 hours.

Scale is heaped-up accumulations of horny epithelium (stratum corneum) that occur in disorders such as psoriasis Psoriasis Psoriasis , seborrheic dermatitis Seborrheic Dermatitis Seborrheic Dermatitis , and fungal infections. Pityriasis rosea Pityriasis Rosea Pityriasis Rosea and chronic dermatitis of any type may be scaly.

Crusts (scabs) consist of dried serum, blood, or pus. Crusting can occur in inflammatory or infectious skin diseases (eg, impetigo Impetigo and Ecthyma Impetigo and Ecthyma ).

Erosions are open areas of skin that result from loss of part or all of the epidermis. Erosions can be traumatic or can occur with various inflammatory or infectious skin diseases. An excoriation is a linear erosion caused by scratching, rubbing, or picking.

Ulcers result from loss of the epidermis and at least part of the dermis. Causes include venous stasis dermatitis Stasis Dermatitis Stasis Dermatitis , physical trauma with or without vascular compromise (eg, caused by decubitus ulcers Pressure Injuries Pressure Injuries or peripheral arterial disease Peripheral Arterial Disease Peripheral Arterial Disease ), infections, and vasculitis Cutaneous Vasculitis Cutaneous Vasculitis .

Petechiae are nonblanchable punctate foci of hemorrhage. Causes include platelet abnormalities (eg, thrombocytopenia, platelet dysfunction Overview of Platelet Disorders Overview of Platelet Disorders ), vasculitis Overview of Vasculitis Overview of Vasculitis , and infections (eg, meningococcemia, Rocky Mountain spotted fever Rocky Mountain Spotted Fever (RMSF) Rocky Mountain Spotted Fever (RMSF) , other rickettsioses).

Purpura is a larger area of hemorrhage that may be palpable. Purpura does not blanch. Palpable purpura is considered the hallmark of leukocytoclastic vasculitis. Purpura may indicate a coagulopathy. Large areas of purpura may be called ecchymoses or, colloquially, bruises.

Atrophy is thinning of the skin, which may appear dry and wrinkled, resembling cigarette paper. Atrophy may be caused by chronic sun exposure, aging, and some inflammatory and neoplastic skin diseases, including cutaneous T-cell lymphoma Cutaneous T-cell Lymphomas (CTCL) Cutaneous T-cell Lymphomas (CTCL) and lupus erythematosus Variant Forms of Lupus Systemic lupus erythematosus is a chronic, multisystem, inflammatory disorder of autoimmune etiology, occurring predominantly in young women. Common manifestations may include arthralgias and... read more Variant Forms of Lupus . Atrophy also may result from long-term use of potent topical corticosteroids.

Scars are areas of fibrosis that replace normal skin after injury. Some scars become hypertrophic or thickened and raised. Keloids Keloids Keloids are hypertrophic scars that extend beyond the original wound margin.

Telangiectases are foci of small, permanently dilated blood vessels that may occur in areas of sun damage, rosacea Rosacea Rosacea , systemic diseases (especially systemic sclerosis Systemic Sclerosis Systemic Sclerosis ), or inherited diseases (eg, ataxia-telangiectasia Ataxia-Telangiectasia Ataxia-Telangiectasia , hereditary hemorrhagic telangiectasia Hereditary Hemorrhagic Telangiectasia Hereditary Hemorrhagic Telangiectasia ) or after long-term therapy with topical fluorinated corticosteroids.

Lesion Configuration (Secondary Morphology)

Configuration is the shape of single lesions and the arrangement of clusters of lesions.

Linear lesions take on the shape of a straight line and are suggestive of some forms of contact dermatitis Contact Dermatitis Contact Dermatitis , linear epidermal nevi, and lichen striatus. Excoriations resulting from scratching are typically linear.

Nummular lesions are circular or coin-shaped; an example is nummular dermatitis Nummular Dermatitis Nummular Dermatitis (nummular eczema).

Target (bull’s-eye or iris) lesions appear as rings with central duskiness and are classic for erythema multiforme Erythema Multiforme Erythema Multiforme .

Serpiginous lesions have linear, branched, and curving elements. Examples include some fungal and parasitic infections (eg, cutaneous larva migrans Cutaneous Larva Migrans Cutaneous Larva Migrans ).

Reticulated lesions have a lacy or networked pattern. Examples include cutis marmorata and livedo reticularis.

Herpetiform describes grouped papules or vesicles arranged like those of a herpes simplex infection Herpes Simplex Virus (HSV) Infections Herpes Simplex Virus (HSV) Infections .

Zosteriform describes lesions clustered in a dermatomal distribution similar to those of herpes zoster Herpes Zoster Herpes Zoster .

Texture of Skin Lesions

Some skin lesions have a visible or palpable texture that suggests a diagnosis.

Verrucous lesions have an irregular, pebbly, or rough surface. Examples include warts Warts Warts and seborrheic keratoses Seborrheic Keratoses Seborrheic Keratoses .

Lichenification is thickening of the skin with accentuation of normal skin markings; it results from repeated scratching or rubbing.

Induration, or deep thickening of the skin, can result from edema, inflammation, or infiltration, including by cancer. Indurated skin has a hard, resistant feeling. Induration is characteristic of panniculitis Panniculitis Panniculitis , some skin infections, and cutaneous metastatic cancers.

Umbilicated lesions have a central indentation and are usually viral. Examples include molluscum contagiosum Molluscum Contagiosum Molluscum Contagiosum and herpes simplex Herpes Simplex Virus (HSV) Infections Herpes Simplex Virus (HSV) Infections .

Xanthomas, which are yellowish, waxy lesions, may be idiopathic or may occur in patients who have lipid disorders.

Location and Distribution of Skin Lesions

It is important to note whether

  • Lesions are single or multiple.

  • Particular body parts are affected (eg, palms or soles, scalp, mucosal membranes).

  • Distribution is random or patterned, symmetric or asymmetric.

  • Lesions are on sun-exposed or protected skin.

Although few patterns are pathognomonic, some are consistent with certain diseases.

Psoriasis Psoriasis Psoriasis frequently affects the scalp, extensor surfaces of the elbows and knees, umbilicus, and the gluteal cleft.

Lichen planus Lichen Planus Lichen Planus frequently arises on the wrists, forearms, genitals, and lower legs.

Vitiligo Vitiligo Vitiligo may be patchy and isolated or may group around the distal extremities and face, particularly around the eyes and mouth.

Hidradenitis suppurativa Hidradenitis Suppurativa Hidradenitis Suppurativa involves skin containing a high density of apocrine glands, including the axillae, groin, and under the breasts.

Color of Skin Lesions

When examining the color of skin, health care professionals should note that the natural color of a patient's skin can change the appearance of colors.

Red skin (erythema) can result from many different inflammatory or infectious diseases. Cutaneous tumors are often pink or red. Superficial vascular lesions such as port-wine stains may appear red.

Orange skin is most often seen in hypercarotenemia, a usually benign condition of carotene deposition after excess dietary ingestion of beta-carotene.

Violet skin may result from cutaneous hemorrhage or vasculitis Overview of Vasculitis Overview of Vasculitis . Vascular lesions or tumors, such as Kaposi sarcoma Kaposi Sarcoma Kaposi Sarcoma and hemangiomas, can appear purple. A lilac color of the eyelids or heliotrope eruption is characteristic of dermatomyositis Autoimmune Myositis Autoimmune Myositis .

Shades of blue, silver, and gray can result from deposition of medications or metals in the skin, including minocycline, amiodarone, and silver (argyria). Ischemic skin appears purple to gray in color. Deep dermal nevi appear blue.

Black skin lesions may be melanocytic, including nevi and melanoma Melanoma Melanoma . Black eschars are collections of dead skin that can arise from infarction, which may be caused by infection (eg, anthrax Anthrax Anthrax , angioinvasive fungi including Rhizopus, meningococcemia Meningococcal Diseases Meningococcal Diseases ), calciphylaxis Calciphylaxis All patients undergoing long-term renal replacement therapy (RRT) develop accompanying metabolic and other disorders. These disorders require appropriate attention and adjunctive treatment.... read more Calciphylaxis , arterial insufficiency, or vasculitis Cutaneous Vasculitis Cutaneous Vasculitis .

Other Clinical Signs of Skin Lesions

Dermatographism (dermographism) is the appearance of an urticarial wheal after focal pressure (eg, stroking or scratching the skin) in the distribution of the pressure. Up to 5% of patients may exhibit this sign, which is a form of physical urticaria.

Darier sign refers to rapid swelling of a lesion when stroked. It occurs in patients with urticaria pigmentosa or mastocytosis Mastocytosis and Mast Cell Activation Syndrome Mastocytosis and Mast Cell Activation Syndrome .

Nikolsky sign is epidermal shearing that occurs with gentle lateral pressure on seemingly uninvolved skin in patients with toxic epidermal necrolysis Stevens-Johnson Syndrome (SJS) and Toxic Epidermal Necrolysis (TEN) Stevens-Johnson Syndrome (SJS) and Toxic Epidermal Necrolysis (TEN) and some autoimmune bullous diseases Introduction to Bullous Diseases .

Auspitz sign is the appearance of pinpoint bleeding after scale is removed from plaques in psoriasis Psoriasis Psoriasis .

Koebner phenomenon describes the development of lesions within areas of trauma (eg, caused by scratching, rubbing, or injury). Psoriasis frequently exhibits this phenomenon, as may lichen planus Lichen Planus Lichen Planus , often resulting in linear lesions.

Drugs Mentioned In This Article

Drug Name Select Trade
Amzeeq, Arestin, Dynacin, Minocin, minolira, Myrac, Solodyn, Ximino, Zilxi
Cordarone, Nexterone, Pacerone
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NOTE: This is the Professional Version. CONSUMERS: View Consumer Version
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