Plaque
What is it?
A plaque is a raised, flat-topped area of skin that is larger than your fingernail (greater than 1 centimeter). Think of it as a plateau rising from your skin's surface - it's elevated but has a relatively flat top rather than being dome-shaped. Plaques often form when smaller bumps (papules) merge together, or they can appear as single large raised areas. They're commonly seen in conditions like psoriasis, where they appear as raised, scaly patches.
What does it look like?
Plaques have distinctive features:
- Raised areas larger than 1 cm (often several centimeters)
- Top surface: Usually flat or slightly rounded, like a plateau
- Borders: Can be well-defined or gradually blend into normal skin
- Colors: Red, pink, skin-colored, purple, or brown
- Surface texture: May be smooth, scaly, rough, or crusty
- Thickness: Noticeably elevated, can be felt easily
- Shapes: Round, oval, irregular, ring-shaped (annular), or snake-like (serpiginous)
Where does it appear?
Plaques commonly develop on:
- Elbows and knees: Classic sites for psoriasis plaques
- Scalp: Psoriasis, seborrheic dermatitis
- Lower back: Psoriasis plaques often appear here
- Trunk: Eczema, mycosis fungoides, granuloma annulare
- Arms and legs: Various conditions
- Anywhere: Drug reactions, lichen planus
Associated features
Plaques may be accompanied by:
- Scaling or flaking (especially in psoriasis)
- Itching, ranging from mild to severe
- Skin thickening from chronic scratching
- Silvery-white scale that flakes off
- Bleeding when scales are removed (Auspitz sign in psoriasis)
- Multiple plaques that may join together
- Changes with treatment or seasons
- Nail changes (with psoriasis or lichen planus)
When to see a doctor
Seek medical attention for:
- New plaques that appear and persist
- Plaques that are spreading or getting thicker
- Severe itching or discomfort
- Plaques with bleeding or signs of infection
- Plaques that don't respond to moisturizers
- Ring-shaped plaques (could be fungal or other conditions)
- Any plaques causing cosmetic concern
- Plaques accompanied by joint pain or other symptoms
References
Primary Sources
Description of Skin Lesions - Merck Manual Professional Edition (2024)
- URL: https://www.merckmanuals.com/professional/dermatologic-disorders/approach-to-the-dermatologic-patient/description-of-skin-lesions
- Key findings: Plaques as palpable lesions >10mm, elevated or depressed, may be flat-topped or rounded
Terminology in Dermatology - DermNet NZ (2024)
- URL: https://dermnetnz.org/topics/terminology
- Key findings: Plaque as circumscribed lesion >1cm, often elevated, with various configurations
Clinical Dermatology Classification - AccessMedicine McGraw Hill (2024)
- URL: https://accessmedicine.mhmedical.com/content.aspx?bookid=3171§ionid=266026462
- Key findings: Morphological features distinguishing plaques from papules by size and configuration
Additional Sources
- Primary Lesions Guide - UTMB Dermatology - URL: https://www.utmb.edu/pedi_ed/CoreV2/Dermatology/page_07.htm - Accessed: 2025-09-30
- Benign Skin Lesions - Medscape - URL: https://emedicine.medscape.com/article/1294801-overview - Accessed: 2025-09-30
Research Notes
- URL: https://pubmed.ncbi.nlm.nih.gov/ - Topic researched: Plaque morphology, psoriasis plaques characteristics
- URL: https://dermnetnz.org/ - Topic researched: Plaque configurations (annular, serpiginous patterns)