A skin disease that causes red, itchy, or scaly patches, usually on the knees, elbows, trunk, and scalp, occurring in cycles of flare-ups that may last for weeks or months before subsiding. 
Types of psoriasis, classified in accordance with location on the body:

  • Plaque psoriasis
  • Nail psoriasis
  • Guttate psoriasis
  • Inverse psoriasis
  • Pustular psoriasis 
  • Erythrodermic psoriasis
  • Psoriatic arthritis 

Common Symptoms

Red patches of skin covered with thick, silvery scales, spots of scaling that are smaller (tend to see this in children), dry/cracked skin prone to bleeding, itching or burning skin, sore patches of skin, ridged/thicker nails, joint pain, plaques of varying sizes.

Coexisting Diseases and Conditions

Having psoriasis makes individuals more susceptible to also developing psoriatic arthritis, eye conditions, type 2 diabetes, high blood pressure, cardiovascular disease, other autoimmune diseases, depression, metabolic syndrome, inflammatory bowel disease, and cardiovascular disease.

Recent research shows that inflammatory bowel disease (Crohn’s disease and ulcerative colitis) may lead to the development of psoriasis.

Risk Factors and Prevalence

Cigarette smoking, overeating or metabolic disorder, hypertension, diabetes, dyslipidemia (elevation of plasma cholesterol, triglycerides (TGs), or both, or a low high density lipoprotein (HDL) cholesterol level, air pollution, drug use, and having a family history of psoriasis.
Additional environmental triggers may include infections or illnesses, dry/cold weather, skin injuries, stress, heavy alcohol consumption, medications, and fast withdrawal of oral/systemic corticosteroids.


  1. Article Sources and Footnotes
    1. de Oliveira, M. de F. S. P., Rocha, B. de O., & Duarte, G. V. (2015). Psoriasis: Classical and emerging comorbidities. Anais Brasileiros de Dermatologia, 90(1), 9–20.

    2. Gottlieb, A. B., Chao, C., & Dann, F. (2008). Psoriasis comorbidities. The Journal of Dermatological Treatment, 19(1), 5–21.

    3. Kamiya, K., Kishimoto, M., Sugai, J., Komine, M., & Ohtsuki, M. (2019). Risk Factors for the Development of Psoriasis. International Journal of Molecular Sciences, 20(18), 4347.

    4. Psoriasis—Symptoms and causes. (n.d.). Mayo Clinic. Retrieved July 9, 2021, from