Derm Terms

A flat, nonpalpable lesion usually < 10 mm in diameter. Represents a change in color and is not raised or depressed compared to the skin surface.

Examples include freckles, flat moles, tattoos, port-wine stains, and the rashes of rickettsial infections, rubella, measles, and some allergic drug eruptions.

A large macule

An elevated lesion, usually < 10 mm in diameter, that can be felt or palpated.

Examples include nevi, warts, lichen planus, insect bites, seborrheic and actinic keratoses, some lesions of acne, and skin cancers.

A palpable lesion > 10 mm in diameter that is elevated or depressed compared to the skin surface. It may
be flat topped or rounded. Lesions of psoriasis and granuloma annulare commonly form one.

A firm papule or lesion that extends into the dermis or subcutaneous tissue.

Examples include cysts, lipomas, and fibromas.

A small, clear, fluid-filled blister < 10 mm in diameter.

Characteristic of herpes infections, acute allergic contact dermatitis, and some autoimmune blistering disorders (eg, dermatitis herpetiformis).

Clear fluid-filled blisters > 10 mm in diameter.

These may be caused by burns, bites, irritant or allergic contact dermatitis, and drug reactions. This is seen in classic autoimmune diseases such as pemphigus vulgaris and bullous pemphigoid. It also
may occur in inherited disorders of skin fragility.

Vesicles that contain pus.

Common in bacterial infections, folliculitis, and may arise in some inflammatory diseases including pustular psoriasis.

Characterized by elevated lesions caused by localized edema. A common manifestation of hypersensitivity to drugs, stings or bites, autoimmunity, and, less commonly, physical stimuli including temperature, pressure, and sunlight. Typically lasts < 24 h.

Heaped-up accumulations of horny epithelium seen in diseases such as psoriasis, seborrheic dermatitis, and fungal infections. May also be seen in pityriasis rosea and chronic dermatitis of any type.

Consist of dried serum, blood, or pus. Can occur in inflammatory or infectious skin diseases (eg, impetigo).

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

Result from loss of the epidermis and at least part of the dermis. Causes include venous stasis dermatitis, physical trauma with or without vascular compromise (eg, from decubitus ulcers, peripheral arterial
disease), infections, and vasculitis.

Nonblanchable punctate foci of hemorrhage. Causes include platelet abnormalities (eg, thrombocytopenia, platelet dysfunction), vasculitis, and infections (eg, meningococcemia, Rocky Mountain spotted fever, other rickettsioses).

A larger area of hemorrhage that may be palpable. May
indicate a coagulopathy. Large areas may be called ecchymoses or, colloquially, bruises.

A large area of purpura

Thinning of the skin, which may appear dry and wrinkled, resembling cigarette paper. May be caused by chronic sun exposure, aging, and some inflammatory and/or neoplastic skin diseases. Also may result from long-term use of potent topical corticosteroids.

Areas of fibrosis that replace normal skin after injury.

A focus of small, permanently dilated blood vessels that are most often idiopathic but may occur in rosacea, systemic diseases (especially scleroderma), or inherited diseases, or after long-term therapy with
topical fluorinated corticosteroids.

These lesions take on the shape of a straight line and are suggestive of some forms of contact dermatitis, epidermal nevi, and lichen striatus.

These lesions are rings with central clearing. Examples include granuloma annulare, some drug eruptions, some dermatophyte infections (eg, ringworm), and secondary syphilis.

These lesions are circular or coin-shaped.

These lesions appear as rings with central duskiness and are classic for erythema multiforme.

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

These lesions have a lacy or networked pattern. An example is cutis marmorata.

Describes grouped papules or vesicles arranged like those of a herpes simplex infection.

Describes lesions clustered in a dermatomal distribution similar to herpes zoster.

These lesions have an irregular, pebbly, or rough surface. Examples include warts and seborrheic keratoses.

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

Deep thickening of the skin which can result from edema, inflammation, or infiltration, including by cancer. Has a hard, resistant feeling. Characteristic of such skin diseases as panniculitis, some skin infections, and cutaneous metastatic cancers.

These lesions have a central indentation and are usually viral. Examples include molluscum contagiosum and herpes simplex.

Yellowish, waxy lesions which may occur with a lipid disorder.