What caused this rash that resists antiviral therapy?

Case : At 1 week postpartum, a 32-year-old woman presents with an itchy rash of sudden onset. Famciclovir, 500 mg bid, is prescribed, but the rash persists.

What do you suspect?

A. Pruritic urticarial papules and
plaques of pregnancy (PUPPP).
B. Grover disease.
C. Staphylococcal infection.
D. Candida folliculitis.
E. Scabies.

Which of the following diagnostic tests would you order?

F. Bacterial culture.
G. Fungal culture.
H. Viral culture.
I.  Biopsy.
J. Potassium hydroxide examination.

Which of the following would you prescribe for this breastfeeding mother pending the test results?

K. Cephalexin.
L. Mupirocin.
M.Fluconazole.
N.Valaciclovir/famciclovir.
O.Triamcinolone cream.

Case 4: Staphylococcal infection

A bacterial culture, F, revealed Staphylococcus aureus, C, that was not resistant to methicillin. The rash responded to combination therapy with cephalexin, K, and mupirocin, L.

PUPPP usually begins in the third trimester and is more intensely pruritic than this patient’s rash. Scabies is also more pruritic, and the eruption would be more widespread. Grover disease is characterized by slightly crusted, erythematous, pruritic papules that occur primarily on the trunk of middle-aged and elderly persons. Candida folliculitis is a possibility that would have been ruled out by the bacterial culture.