The reason why you catch a cold as soon as you take psoriasis medicine mainly lies in the fact that psoriasis patients themselves have low immunity and are prone to complications of colds if they don’t pay attention to warmth, which has little to do with taking psoriasis medication itself. Psoriasis is an immune-mediated, chronic, relapsing, inflammatory, systemic disease induced by a combination of genetic and environmental effects. The exact cause of psoriasis is still unclear, psoriasis is characterized by abnormal differentiation of T cells, infiltration and excessive proliferation of skin keratinocytes, and generally the lower the immunity the more likely to induce psoriasis, so patients with psoriasis tend to have low immunity. Patients with low immunity, if usually do not pay attention to keep warm, do not timely care, easy to induce the occurrence of cold, so psoriasis patients with cold and taking medication does not have much to do with. It is recommended that patients pay attention to supplemental nutrition in daily life and avoid triggering factors so as not to aggravate the condition.