Psoriasis: an immune system disease, not just a skin condition

Psoriasis is a chronic inflammatory disease, driven by the immune system, in which skin cells renew far too quickly, building up into thick plaques with whitish scales. It isn’t contagious, and it has a strong genetic component.

Where it shows up

Most often on the elbows, knees, scalp and lower back, though it can appear anywhere on the body, including the nails. Skin trauma, such as a cut or sunburn, can trigger new plaques in the affected area, a phenomenon known as the Koebner phenomenon.

Triggers that can set off flares

Infections, especially streptococcal throat infections.
Intense emotional stress.
Certain medications, such as lithium or some beta-blockers.
Trauma or injury to the skin.

More than skin deep

Up to three in ten people with psoriasis develop psoriatic arthritis, with joint pain and inflammation. Psoriasis is also linked to higher cardiovascular risk, which makes it especially important to manage other risk factors, such as blood pressure and cholesterol, in people who have it.

Treatment

Mild cases: topical corticosteroids and vitamin D analogues.
Phototherapy: controlled exposure to ultraviolet light, useful for more extensive disease.
Systemic treatment: methotrexate, or biologics targeting the IL-17 and IL-23 inflammatory pathways, reserved for moderate to severe cases.

This article is for information only and does not replace a medical consultation.

Sources

Menter A, Gelfand JM, Connor C, et al. Joint AAD-NPF Guidelines of Care for the Management of Psoriasis with Biologics. Journal of the American Academy of Dermatology. 2019
National Psoriasis Foundation