Psoriasis is a long term immune mediated condition that causes skin cells to build up more quickly than normal. It produces inflamed, scaly patches and can also affect the nails and joints. Psoriasis is not contagious.
Symptoms
Plaque psoriasis, the most common type, causes well defined patches covered with scale. Patches may look red or pink on lighter skin and purple, grey or dark brown on darker skin. They can itch, burn, crack or bleed.
Common areas include the scalp, elbows, knees and lower back, although any skin can be affected. Nail psoriasis may cause pits, thickening, color changes or separation from the nail bed.
Types of psoriasis
- Plaque psoriasis causes raised scaly patches.
- Guttate psoriasis causes many small scaly spots and may follow a throat infection.
- Inverse psoriasis affects skin folds and often looks smooth and inflamed.
- Pustular psoriasis causes pus filled bumps that are not infectious.
- Erythrodermic psoriasis causes widespread inflammation and skin shedding and is a medical emergency.
Triggers and associated health
Flares can follow infection, skin injury, stress, smoking, heavy alcohol use or certain medicines. Do not stop prescribed medicine without medical advice.
Psoriasis is associated with a higher risk of psoriatic arthritis and some cardiovascular and metabolic conditions. New joint pain, swelling, prolonged morning stiffness, heel pain or a swollen finger or toe should be assessed early.
Diagnosis
A clinician usually diagnoses psoriasis by examining the skin, scalp and nails. A small skin biopsy is occasionally needed when another condition is possible. The effect on sleep, mood, work and daily life matters as well as the visible area involved.
See our Skin Health section for related conditions and skin care information.
Treatment
Regular emollients help reduce dryness and scaling. Prescription topical treatments may include corticosteroids, vitamin D analogues, calcineurin inhibitors or other medicines selected for the body area and type of psoriasis. Strong steroid products require careful instructions because inappropriate use can thin the skin or cause rebound problems.
More extensive or difficult psoriasis may be treated with supervised ultraviolet light therapy, tablets or injections that target the immune system. These medicines require assessment and monitoring for infections and other side effects.
Everyday care
Moisturise regularly, avoid picking scales and use treatments exactly as directed. Maintain a healthy weight, avoid smoking and keep alcohol moderate. Discuss vaccination and infection precautions before or during immune modifying treatment.
When to seek urgent help
Seek urgent medical care if psoriasis suddenly becomes widespread with intense redness or darkening, skin shedding, fever, chills, rapid heartbeat, dehydration or severe weakness. Widespread pustules with fever also need immediate assessment.
Arrange routine medical advice if the diagnosis is uncertain, symptoms affect daily life, treatment is not working, or joint symptoms develop. Seek urgent mental health support if the condition contributes to thoughts of self harm or suicide.
Sources
- NHS: Psoriasis
- National Institute of Arthritis and Musculoskeletal and Skin Diseases: Psoriasis
- NIAMS: Psoriasis diagnosis and treatment
- American Academy of Dermatology: Psoriasis treatment
Using this information
This information supports, but does not replace, an individual medical assessment. Treatment varies by psoriasis type, body area, severity, other health conditions and pregnancy plans.
Reviewed: 28 August 2026