Dermatology for the Non-Dermatologist
May 30 – June 3, 2018 - 1 -
Fundamentals of Dermatology
Daniel J. Van Durme, M.D.
Fundamentals of Dermatology
Describing Rashes and Lesions
History remains ESSENTIAL to establish diagnosis – duration, treatments, prior history of skin
conditions, drug use, systemic illness, etc., etc. Historical characteristics of lesions and rashes are also
key elements of the description. Painful vs. painless? Pruritic? Burning sensation?
Key descriptive elements – 1- definition and morphology of the lesion, 2- location and the extent of the
disease.
DEFINITIONS:
Atrophy: Thinning of the epidermis and/or dermis causing a shiny appearance or fine wrinkling
and/or depression of the skin (common causes: steroids, sudden weight gain, “stretch marks”)
Bulla: Circumscribed superficial collection of fluid below or within the epidermis > 5mm (if <5mm
vesicle), may be formed by the coalescence of vesicles (blister)
Burrow: A linear, “threadlike” elevation of the skin, typically a few millimeters long. (scabies)
Comedo: A plugged sebaceous follicle, such as closed (whitehead) & open comedones (blackhead) in
acne
Crust: Dried residue of serum, blood or pus (scab)
Cyst: A circumscribed, usually slightly compressible, round, walled lesion, below the epidermis, may
be filled with fluid or semi-solid material (sebaceous cyst, cystic acne)
Dermatitis: nonspecific term for inflammation of the skin (many possible causes); may be a specific
condition, e.g. atopic dermatitis
Eczema: a generic term for acute or chronic inflammatory conditions of the skin. Typically appears
erythematous, edematous, papular, vesicular, and crusted. When chronic it leads to lichenification
and sometimes hyperpigmentation. Usually itches and burns. May be specific condition; e.g.,
“nummular eczema”, or nonspecific term “eczematous eruption” or “hand eczema”
Erosion: Loss of portion of the epidermis, superficial and non-scarring (area after a vesicle or bulla
ruptures); also see ulcer
Eruption: a “breaking out” of the skin or rapidly developing dermatosis
Erythematous: a 5 syllable word for “red”
Exanthem: a skin eruption typically due to a viral (or some bacterial) systemic disease
Excoriation: similar to erosion, but from self-inflicted removal of some or all of the epidermis (scratch)
Fissure: Vertical “cut” extending into the dermis. (anal fissure, “cracked skin” from T. pedis)
Hive: (see wheal)
Hyperkeratotic: Localized thickening of the epidermis (stratum corneum layer), (wart, callous)
Keloid: Abnormally hypertrophied scar
Lichenification: Leathery induration and thickening of the skin with hyperkeratosis due to long standing
scratching or irritation, marked prominence of normal skin lines (many chronic dermatoses)
Macule: Flat, nonpalpable lesion with color change (hyper- or hypopigmented, erythematous) less than
5-10mm (larger than 5-10mm patch) (freckles, flat nevi)
Morphology: Shape of the primary lesion, e.g. linear, round.
Nodule: A solid lesion (5-20mm) with an appreciable deep (dermal and/or subcutaneous) component,
(lipoma, dermatofibroma)
