Dermatology terms can often feel like a whole new language. Whether you’re a nursing student, medical professional, or simply trying to understand a clinical diagnosis, learning how skin lesions are classified is the first step toward accurate identification. Skin lesions are broadly categorized into Primary Lesions (the initial physical manifestation), Secondary Lesions (changes that result from evolution, damage, or healing of primary lesions), and Patterns (how multiple lesions are arranged on the body).
Here is a breakdown of common skin lesions, their clinical descriptions, and classic examples.
Primary lesions are the baseline physical characteristics of a skin condition. They indicate the original change in skin structure, color, or texture.
| Lesion | Description | Classic Example |
|---|---|---|
| Macule | Flat discoloration, usually less than 1 cm in diameter | Freckle |
| Patch | Flat area of skin discoloration, larger than a macule | Vitiligo |
| Papule | Raised lesion, less than 1 cm; may be the same or different color than surrounding skin | Raised nevus (mole) |
| Plaque | Raised lesion, ≥1 cm; may be the same or different color than surrounding skin | Psoriasis |
| Vesicle | Fluid-filled, less than 1 cm | Varicella (Chickenpox) |
| Bulla | Fluid-filled, ≥1 cm | Blister with second-degree burn |
| Pustule | Vesicle-like lesion filled with purulent content (pus) | Impetigo, acne |
| Nodule | Raised lesion, ≥1 cm, usually mobile | Epidermal cyst |
| Wheal | Circumscribed area of skin edema (swelling) | Hive (Urticaria) |
| Purpura | Lesions caused by red blood cells leaving circulation and becoming trapped in the skin | Petechiae, ecchymosis |
Secondary lesions develop over time due to external factors such as scratching, infection, or the natural progression and healing of a primary lesion.
| Lesion | Description | Classic Example |
|---|---|---|
| Excoriation | Marks produced by scratching | Pruritic skin diseases |
| Lichenification | Skin thickening resembling callus formation | Areas of recurrent scratching |
| Fissure | Narrow linear crack into epidermis, exposing dermis | Split lip, athlete’s foot |
| Erosion | Partial focal loss of epidermis; heals without scarring | Area exposed after a bullous lesion opens |
| Ulcer | Loss of epidermis and dermis; heals with scarring | Pressure sore |
| Scale | Raised, flaking lesion | Dandruff, psoriasis |
| Atrophy | Loss of skin markings and full skin thickness | Area treated excessively with high-potency corticosteroids |
Beyond individual characteristics, observing the spatial arrangement or distribution pattern of lesions provides critical diagnostic clues.
Clinical Reference: James WD, Berger TG, Elston DM. Andrews’ Diseases of the Skin: Clinical Dermatology. 12th ed. Philadelphia, PA: Elsevier; 2016.
