A 22-year-old man presents with a 6-week eruption of polymorphous papules at various stages of evolution—fresh erythematous macules with central hemorrhagic crusting, vesicular lesions, and older hypopigmented varioliform scars distributed over the trunk and flexor surfaces. Skin biopsy shows parakeratotic scale-crust, focal epidermal necrosis with lymphocyte exocytosis, interface dermatitis, and a wedge-shaped lymphocytic infiltrate with extravasated red blood cells. A diagnosis of Pityriasis Lichenoides Et Varioliformis Acuta (PLEVA/Mucha-Habermann disease) is made. For management of this extensive disease, the first-line systemic therapy marked as **A** in the diagram is most appropriate. Which of the following best describes the mechanism and indication for this treatment class?
A. Antifungal agents targeting presumed dermatophyte or Malassezia colonization as the primary pathogenic trigger
B. Acyclovir 800 mg five times daily to suppress occult herpes simplex or varicella-zoster reactivation driving the necrotic lesions
C. Topical corticosteroids applied twice daily as monotherapy for suppression of the polymorphous eruption and prevention of scar formation
D. Oral tetracyclines (doxycycline or minocycline) given for 8–12 weeks for their anti-inflammatory effects in T-cell-mediated papulonecrotic disorders
Explanation
Why oral tetracyclines (option 0) is right
The clinical anchor from Bolognia Dermatology explicitly identifies oral tetracyclines (doxycycline 100 mg twice daily, minocycline, or erythromycin in children) as first-line therapy for extensive or persistent PLEVA. The mechanism is their potent anti-inflammatory effect rather than antimicrobial action—they suppress the CD8-positive T-cell-mediated response that drives this polymorphous papulonecrotic eruption. The standard duration is 8–12 weeks. This is the correct answer for the structure marked A in the diagram.
Why each distractor is wrong
Option 1 (Topical corticosteroids alone): While topical corticosteroids are appropriate for mild disease and emollients, they are insufficient as monotherapy for extensive PLEVA. The textbook reserves topical agents only for mild cases; extensive disease requires systemic therapy—specifically tetracyclines or phototherapy.
Option 2 (Antifungal agents): PLEVA is a T-cell-mediated papulonecrotic disorder with no established fungal etiology. Antifungal therapy is not indicated and would not address the underlying lymphocytic infiltrate or necrotic pathology. This is a common misconception in polymorphous eruptions.
Option 3 (Acyclovir): Although herpes simplex and varicella-zoster are in the differential diagnosis, PLEVA is distinguished by its polymorphous lesions at different stages, characteristic histology (interface dermatitis, wedge-shaped infiltrate), and lack of response to antivirals. Acyclovir is not first-line and would not treat the T-cell-mediated process.
High-YieldNEET PG
PLEVA = tetracyclines (8–12 weeks) for extensive disease; methotrexate reserved for refractory chronic or severe (FUMHD) cases.
Bolognia Dermatology, 5th ed., Ch. on Pityriasis Lichenoides
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