HPI: A 3-month-old Caucasian male presents for evaluation of rash. His mother noted that for the past 8 weeks, the patient had been developing recurrent crops of "red bumps" on his arms and trunk, as well as pustules and vesicles on his hands and feet. He has been treated presumptively for scabies multiple times without improvement. He has been seen by his pediatrician and in the emergency room for this rash, with workup negative for HSV/VZV PCR and no growth of bacterial cultures of vesicle contents. Mom denies any other family member having a similar rash or being itchy.
PMH: Otherwise healthy, born full term in an uncomplicated delivery. Thrush about 1 month ago.
Social Hx: Breast-feeding normally.
Family Hx: Noncontributory.
Medications: Tylenol prn, Benadryl prn.
Physical exam: On the soles of his feet, there are erythematous macules and pustules with erythematous bases (Figure 1A). On his right lower back, there is a 3mm red firm papule with central crusting (Figure 1B).
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