HOUSTON – Although scientists still don’t know exactly what causes psoriasis, stress is a well-known trigger, according to the National Psoriasis Foundation. “[They’re] stressed, maybe they’re not eating as well, so it’s all tied together, most likely,” Mehta said. Food intake doesn’t cause psoriasis, but it could be the cause of inflammation, which doesn’t help. She says increased handwashing during the pandemic won’t affect psoriasis patients as much as eczema patients, so that’s less of a concern. Even the fumes can cause skin problems among people who have sensitive skin.