Psoriasis is the common name for psoriasis, and the sudden redness of psoriasis may be caused by factors such as climate change, bad mood, infection, diet and other factors that cause psoriasis to worsen or relapse. 1. Climate change: cold climate can aggravate the symptoms of psoriasis, which usually manifests as heavy in winter and light in summer. 2. Bad mood: excessive tension, anxiety, stress stimulation, often lead to psoriasis recurrence aggravation. 3. Infection: when the organism is infected with bacteria, virus, fungus, etc., it can induce psoriasis to produce or recur, and the recurrence of psoriasis can be manifested as redness of the affected area. 4. Dietary or life factors: smoking, alcoholism, eating spicy and stimulating food, etc., may also lead to the recurrence of psoriasis. Psoriasis is almost cured suddenly redness may also be seen in other reasons, the patient should consult the doctor in time, clear cause of the disease in the professional doctor’s diagnosis and under the guidance of the treatment.