Medically reviewed by Debra Rose Wilson, Ph.D., MSN, R.N., IBCLC, AHN-BC, CHT — Written by Elea Carey — Updated on September 17, 2018
What is psoriasis?
Psoriasis is a chronic condition with no known cure. It’s caused by improper functioning of your immune system. The condition makes new skin cells develop unnecessarily on top of your existing, healthy skin. The resulting patches can appear anywhere on the body, but most often affect the skin at the elbows, knees, scalp, fingernails, and toenails. Psoriasis can also generate joint inflammation, which is known as psoriatic arthritis.
The extra skin cells group together in gray, itchy, and even painful patches that can crack and bleed. Though it’s a chronic condition, the harshest symptoms aren’t always present and noticeable. Symptoms can come and go for different periods of time. Patches can also shift in size and appear in different places than they did during prior outbreaks.
Are tomatoes forbidden?
Stories have circulated that eating nightshade fruits and vegetables — those derived from the plant family Solanaceae — can trigger flare-ups of psoriasis. Nightshade fruits and vegetables include tomatoes as well as white potatoes, eggplants, and pepper-derived foods like paprika and cayenne pepper (but not black pepper, which comes from a different plant altogether).
The evidence that avoiding nightshades can help prevent psoriasis is anecdotal. Scientific studies have yet to show a clear connection between eating nightshades and worsening outbreaks. If tomatoes or other nightshades seem to make your condition worse, eliminate them one by one, and keep a food diary to note changes.
