The disease can begin at an early age following a streptococcal upper respiratory infection. Guttate psoriasis with numerous small lesions rapidly appears following this infection. Fortunately this form of psoriasis may clear completely falling a short course of topical medication and light exposure.
Most people who have this disease slowly develop chronic red scaly plaques that tend to last for months or years. Itching is of variable intensity. Scratching causes the plaques to persist. A common presentation is to have plaques first began on the elbows and knees.
A plaque may form in an area of trauma. Trauma-induced psoriasis is called Koebner phenomenon. Stress may cause psoriasis. A major flare may follow a traumatic event such as a car accident. There are many so-called co-morbidities. There may be an increase in incidence of obesity alcoholism and depression.