Clinical features and course of generalized pustular psoriasis in Korea

The clinical course of generalized pustular psoriasis (GPP) is variable and unpredictable. Sufficient data on the clinical course of the disease has not been reported due to its rarity. To investigate the clinical features and course of GPP according to its subtypes, medical records of patients diagnosed with GPP from 2002 to 2012 at two tertiary hospitals were reviewed. The data included patient demographics, associated symptoms, aggravating factors, patterns of relapse and prognosis. Thirty-three patients with GPP were included in our study, with a mean age of 45.6 years and a male : female ratio of 1:1.2. Patients were categorized based on the following subtypes: acute GPP, 21 (63.6%); GPP of pregnancy, two (6.1%); juvenile GPP, three (9.1%); and annular GPP, seven (21.2%). In the acute GPP population, skin lesions cleared within 2 months in 11 (73.3%) patients, and six (40.0%) of these had no relapse. Severe complications, abortion or death, were observed in two patients (100.0%) with GPP of pregnancy. Nineteen (76.0%) of the GPP patients experienced persistence or relapse of skin lesions. The patterns of skin lesions upon relapse included plaques in six patients (31.6%), pustules in eight patients (42.1%), and plaques and pustules in five patients (26.3%). Among acute GPP patients, 16.7% of patients with no relapse had a history of plaque psoriasis. However, 77.8% of patients with persistence and relapse in their clinical course had a history of plaque psoriasis. In conclusion, our study presents the detailed clinical course of GPP by subtype in Korean patients.