Erythrodermic psoriasis on the back of a 26 year old female Hispanic patient who has stopped taking the drug Ixekizumab (marketed under the name Taltz) to treat the condition. Psoriasis is an autoimmune disease characterised by patches of abnormal skin. Erythrodermic psoriasis occurs when the rash becomes very widespread, leading to reddened, scaly, thickened patches of skin (caused by excessive skin growth). Ixekizumab is a humanised monoclonal antibody drug that blocks interleukin 17A, which is involved in the inflammatory response.