(Choice A) Oral antifungals (eg, fluconazole, itraconazole) can be used to treat intertrigo in patients who have severe infection or fail topical antifungal therapy. Intertrigo is found in warm, moist skinfolds (eg, abdominal, inframammary (see image below).
(Choice B) Foscarnet is used primarily in the treatment of drug-resistant cytomegalovirus. It can be considered for patients with severe VZV illness who fail first-line drugs; however, it would not be used for uncomplicated shingles.
(Choice C) Gabapentin is indicated for postherpetic neuralgia. However, it requires a lengthy period of up-titration and is not useful in acute shingles.
(Choice D) Mupirocin is a topical antibiotic indicated for the treatment of certain secondarily infected skin wounds and for eradication of nasal colonization of methicillin-resistant Staphylococcus aureus.
(Choice E) Penicillins are used in the treatment of mild erysipelas, which presents with erythematous patches with raised, sharply demarcated borders. This patient's vesicular rash and prodromal neuritic symptoms are more consistent with shingles.
(Choice F) Oral glucocorticoids (eg, prednisone) have been suggested as adjuvant treatment for shingles along with acyclovir, but appear to have minimal benefit and do not reduce the risk of postherpetic neuralgia.
Explanation
This patient has an erythematous, vesicular rash consistent with herpes zoster (shingles), which is caused by reactivation of latent varicella-zoster virus (VZV) infection. Following the primary infection (chickenpox), VZV remains dormant in the dorsal root ganglia until emerging from the nerve decades later. Decreased cell-mediated immunity (eg, older age, immunosuppressive medications, HIV) increases the risk of reactivation.
The rash begins with small papules that become confluent and evolve into vesicles or bullae, with subsequent ulceration and crusting in 7-10 days. It is usually limited to a single dermatome but may involve adjacent dermatomes, and a few scattered lesions may develop in distant areas. Most patients have associated neuritic symptoms (eg, itching, burning, allodynia) that may precede the onset of the rash and last up to 4 months. Neuritic pain that persists >4 months is termed postherpetic neuralgia. Treatment with antiviral agents (eg, acyclovir, famciclovir, valacyclovir) shortens the course of acute symptoms and decreases the duration of postherpetic neuralgia, especially if initiated within 72 hours.
Educational objective: Herpes zoster causes a dermatomal rash characterized by small papules that evolve into vesicles or bullae with ulceration and crusting. It is caused by reactivation of varicella zoster virus; decreased cell-mediated immunity (eg, older age, HIV) increases the risk. It is treated with antiviral agents (eg, acyclovir, famciclovir, valacyclovir).
