Clinical meaning
The NP performs systematic dermatological assessment using standardized morphological terminology to accurately describe, document, and communicate skin findings. Precise lesion description is essential for differential diagnosis, appropriate biopsy decisions, and effective dermatology referral.
Primary lesions (arising de novo in previously normal skin) are classified by size and morphology: Flat lesions — macule (<1 cm, flat color change) and patch (>1 cm, flat color change). Elevated solid lesions — papule (<1 cm), plaque (>1 cm, elevated, flat-topped), nodule (>1 cm, deeper, palpable in dermis/subcutis), tumor (>2 cm solid mass). Fluid-filled lesions — vesicle (<1 cm, clear fluid), bulla (>1 cm, clear fluid), pustule (any size, contains purulent material). Transient lesions — wheal (edematous papule/plaque that resolves within 24 hours, as in urticaria).
Secondary lesions result from evolution or manipulation of primary lesions: scale (excess keratinized epithelium), crust (dried serum, blood, or exudate), erosion (superficial loss of epidermis, heals without scarring), ulcer (loss through epidermis into dermis or deeper, heals with scarring), fissure (linear crack in skin), excoriation (linear erosion from scratching), lichenification (thickened skin with accentuated markings from chronic rubbing), atrophy (thinning of epidermis/dermis), scar (fibrous tissue replacing damaged dermis).
Distribution patterns provide critical diagnostic clues: dermatomal (herpes zoster), photodistributed (lupus, drug eruption, polymorphous light eruption), extensor surfaces (psoriasis, dermatitis herpetiformis), flexural/intertriginous (atopic dermatitis in adults, inverse psoriasis), acral (hand-foot-mouth disease, secondary syphilis), linear (contact dermatitis following exposure pattern, lichen striatus), bilateral symmetric (systemic drug eruption, psoriasis).