Pneumocystis pneumonia in patients with immunobullous dermatoses.

Background: Immunobullous dermatoses are usually treated with immunosuppressive agents, which make patients susceptible to pneumocystis pneumonia (PCP). The aim of this study was to evaluate the incidence and clinical characteristics of PCP in patients with immunobullous diseases.
Methods: We analyzed computerized medical records to obtain a retrospective evaluation of the incidence and clinical characteristics of PCP in patients with immunobullous diseases, hospitalized at the Peking Union Medical College Hospital from January 2004 to December 2009.
Results: Of 202 patients with immunobullous disorders, four (1.9%) had PCP; two of them had pemphigus vulgaris (PV), one had pemphigus foliaceus (PF), and one suffered from bullous pemphigoid (BP). All four patients had been treated with corticosteroids and a cytotoxic agent before diagnosis of PCP. Three of the four patients developed PCP within 14 weeks of the diagnosis of an immunobullous disease. Average and maximal prednisone doses were 0.98 mg/kg per day and 1.8 mg/kg per day, respectively. The median durations of prednisone doses >1.0 mg/kg per day and >1.5 mg/kg per day were 6.5 weeks and 4 weeks, respectively. Lymphocyte counts ranged from 330/μl to 1200/μl at the time of diagnosis of PCP. Additional complicating infections were found in three of the four patients. In all four patients, PCP was treated with trimethoprim-sulfamethoxazole and corticosteroids. Skin lesions were under control at the onset of PCP and did not flare during the treatment of PCP; however, two of the four patients died.
Conclusions: Fewer than 2% of subjects in our large series of patients with immunobullous diseases contracted PCP. Nevertheless, it is important to remain alert for PCP in patients with immunobullous diseases who are undergoing treatment with prednisone and cytotoxic agent(s).
(© 2011 The International Society of Dermatology.)