Psoriasis

Psoriasis is a chronic immune-mediated skin disease in which skin cells multiply too quickly, forming thick, scaly, often red or discolored plaques.

The most common form, plaque psoriasis, produces well-defined patches with silvery scale on the elbows, knees, scalp and lower back, though any area can be involved. Other forms include guttate, inverse, pustular and nail psoriasis. The condition runs in families, typically appears in early adulthood, and flares with stress, infections, skin injury and certain medications. Up to a third of people with psoriasis develop psoriatic arthritis.

Dermatologists diagnose it mainly by appearance, occasionally confirming with a skin biopsy, and grade severity by the body surface area affected and the impact on daily life. Cannabinoid receptors are present in skin cells and have been studied in laboratory settings related to inflammation and cell turnover, but clinical research in psoriasis is very limited.