Shasa Hu, MD, a board-certified dermatologist previously told the outlet, “A blistering sunburn can trigger a whole-body psoriasis flare, as sunburn can be thought of as systemic injury to the skin. This is why, although natural sunlight at a very low dose and medical UV therapy are known treatment[s] for psoriasis, sunburn is a big no-no for psoriasis patients. The same goes for tanning bed use.”

Source: https://www.buzzfeed.com/chelseastewart/kim-kardashian-tanning-bed-criticism-response