A localized infection in the skin that causes a swollen, red and painful bump filled with pus. Examples: Acarbuncles and furuncles.
Annular lesion
Rings with central clearing. Examples: granuloma annulare, some drug eruptions, some dermatophyte infections (eg, tinea [ringworm]), and secondary syphilis.
Anular
Con forma de anillo Examples: Granuloma anular, tiña corporal.
Atrophy
Thinning or depression of skin due to a reduction in the amount of underlying tissue. Examples: steroid-induced skin athrophy, atrophoderma of Passini and Pierini.
Bulla
A blister > 10 mm in diameter which contains clear fluid. Examples: pemphigus vulgaris, bullous pemphigoid.
Crust (scab)
Dried serum, blood, or pus. Examples: impetigo.
Ecchymosis
A large collection of blood in the skin > 5 mm in diameter.Commonly known as a bruise, refers to the discoloration of the skin due to the ruptura of the blood vessels bellow the surface of the skin. Causes: Trauma, medical conditions (aplastic anemia, Vitamin K defficiency, renal failures).
Erosion
An open area of skin due to the loss of part or all of the epidermis. Examples: eczema, infectious skin diseases.
Fissure
A cracking or splitting of the skin. Examples: Asteatotic eczem.
Induration
Deep thickening of the skin. Indurated skin has a hard, resistant feeling. Examples: panniculitis, some skin infections, cutaneous metastatic cancers.
Lichenification
An area of thickening of the skin caused by chronic scratching or rubbing. Causes: Dermatitis, eczema, xerosis (dry skin), psoriasis, dermatophyte infections, bug bites, severe anxiety, obsessive-compulsive disorder (OCD).
Linear lesion
A linear shape to a lession often occurs for some external reason, such as scratching; also known as striate, acts as diagnostic clues to many dermatological conditions such as some forms of contact dermatitis, linear epidermal nevi, and lichen striatus, and can present as macules, papules, patches, plaques, vesicles, or nodules. Causes: lesions following Blaschko’s lines, blood vessels, lymphatics, dermatomes.
Macule
A flat, nonpalpable lesion usually < 10 mm in diameter, with a change in color and are not raised or depressed compared to the skin surface. Examples: freckles, flat moles, tattoos, and port-wine stains.
Nodule
A firm papule or elevated and rounded skin lesion that extend into the dermis or subcutaneous tissue. Examples: cysts, lipomas, and dermatofibromas.
Nummular lesion
A circular or coin-shaped lesion; also known as discoid. Examples: nummular dermatitis (nummular eczema).
Papule
An elevated, solid lesion usually < 10 mm in diameter that can be felt or palpated. Examples: nevi, warts, lichen planus, insect bites, seborrheic keratoses, actinic keratoses, some lesions of acne, and skin cancers.
Petechia
Nonblanchable punctate focus of hemorrhage, a visible small collection of blood in the skin. Causes: include platelet abnormalities, vasculitis, and infections such as meningococcemia, rickettsioses.
Plaque
A palpable lesion > 10 mm in diameter, flat topped or rounded, elevated or depressed compared to the skin surface. Examples: psoriasis, granuloma annulare.
Purpura
A larger area of hemorrhage that may be palpable. This does not blanch (become pale) on applying pressure. Examples: Thrombocytopaenic purpura, heparin induced thrombocytopenia, non-thrombocytopaenic purpura.
Pustule
Vesicle that contain pus. Examples: folliculitis, pustular psoriasis.
Reticulated lesion
A skin lesion with a lacy or networked pattern. Examples: cutis marmorata, livedo reticularis.
Scale
A heaped-up accumulation of horny epithelium (stratum corneum). Examples: psoriasis, seborrheic dermatitis, fungal infections.
Scar
A dense collection of collagen fibers which form after an injury to the skin or from surgery. Some scars become hypertrophic or thickened and raised. Examples: Keloids.
Serpiginous lesion
A skin lesion with linear, branched, and curving elements. Examples: some fungal and parasitic infections (eg, cutaneous larva migrans).
Suppuration
A type of acute inflammation characterized by infiltration of neutrophils at the microscopic level and formation of pus at the gross level. Examples: abscess.
Target (bull’s-eye or iris)
Concentric rings like a dartboard; also known as iris lesión. Examples: erythema multiforme.
The full-thickness loss of the epidermis plus at least a portion of the dermis; it may extend into the subcutaneous tissue. This heals with scarring since it is a deep lesion. Causes: venous stasis dermatitis, physical trauma with or without vascular compromise (eg, decubitus ulcers or peripheral arterial disease), infections, vasculitis.
Umbilicated lesion
Lesion with a central indentation, usually viral. Examples: molluscum contagiosum, herpes simplex.
Verrucous lesion
A lesion with an irregular, pebbly, or rough surface. Examples: warts, seborrheic keratoses.
Vesicle
A small, fluid-filled blisters < 10 mm in diameter. Examples: herpes infections, acute allergic contact dermatitis, dermatitis herpetiformis.