Infectious dermatitis should be considered in any patient presenting with pustular lesions. Bacterial culture will easily distinguish these entities, as pustular psoriasis is sterile, while culture of impetigo will generally yield streptococcus or staphylococcus species.
Dr. Femia is a fellow in the dermatology–rheumatology fellowship at Brigham and Women’s Hospital in Boston. She is a diplomat of the American Board of Dermatology.
Dr. Merola is an instructor in the department of dermatology at Harvard Medical School and a fellow in the rheumatology division at Brigham and Women’s Hospital, both in Boston. He is the assistant program director for the combined medicine–dermatology training program and a diplomat of the American Board of Dermatology and the American Board of Internal Medicine.