Psoriasis is a skin disease that causes itchy or sore patches of thick, red skin with silvery scales. You usually get the patches on your elbows, knees, scalp, back, face, palms and feet, but they can show up on other parts of your body. Some people who have psoriasis also get a form of arthritis called psoriatic arthritis.
A problem with your immune system causes psoriasis. In a process called cell turnover, skin cells that grow deep in your skin rise to the surface. Normally, this takes a month. In psoriasis, it happens in just days because your cells rise too fast.
Psoriasis can be hard to diagnose because it can look like other skin diseases. Your doctor might need to look at a small skin sample under a microscope.
Psoriasis can last a long time, even a lifetime. Symptoms come and go. Things that make them worse include
- Dry skin
- Certain medicines
Psoriasis usually occurs in adults. It sometimes runs in families. Treatments include creams, medicines, and light therapy.
NIH: National Institute of Arthritis and Musculoskeletal and Skin Diseases
- About Psoriasis (National Psoriasis Foundation)
- Itchy, Scaly Skin? Living with Psoriasis (National Institutes of Health)
- Psoriasis (American Academy of Family Physicians) Also in Spanish
- Psoriasis (American Academy of Dermatology)
- Spotlight on Psoriasis: Preventing Patches of Itchy, Sore Skin (National Institutes of Health)
- What Is Psoriasis? (National Institute of Arthritis and Musculoskeletal and Skin Diseases) Also in Spanish
- Severe Psoriasis May Make Diabetes Increasingly Likely (11/20/2017, HealthDay)
- Severe Psoriasis Linked to Higher Risk of Earlier Death (09/05/2017, HealthDay)
- Psoriasis Diet: Can Changing Your Diet Treat Psoriasis? (Mayo Foundation for Medical Education and Research)
- Scalp Psoriasis vs. Seborrheic Dermatitis: What's the Difference? (Mayo Foundation for Medical Education and Research)
- Genetics Home Reference: generalized pustular psoriasis (National Library of Medicine)
- Psoriasis (Logical Images)
- ClinicalTrials.gov: Psoriasis (National Institutes of Health)
Journal Articles References and abstracts from MEDLINE/PubMed (National Library of Medicine)
Find an Expert
- Find a Dermatologist (American Academy of Dermatology)
- National Institute of Arthritis and Musculoskeletal and Skin Diseases Also in Spanish
- Psoriasis (Children's Hospital Boston)