A 14-year-old boy presents with sudden onset of multiple small, drop-shaped erythematous papules scattered over his trunk and extremities for 2 weeks. He reports a sore throat 3 weeks ago that resolved spontaneously. On examination, the lesions are <1 cm, with fine scale, and distributed widely across the trunk and limbs. The factor marked **D** in the diagram is suspected as the trigger for this presentation. Which of the following is the most appropriate initial management for this patient?

Explanation

## Why Penicillin V or Amoxicillin for 10 days is right Guttate psoriasis is characterized by drop-shaped (<1 cm) erythematous papules with fine scale, typically distributed on the trunk and extremities. The key clinical anchor is that **post-streptococcal pharyngitis is the trigger in ~80% of cases**, particularly in children and adolescents. The factor marked **D** (post-streptococcal trigger) directly indicates active or recent streptococcal infection. Treatment of the underlying streptococcal infection with penicillin V or amoxicillin for 10 days is the most appropriate initial step, as it addresses the trigger, may improve psoriasis, and prevents complications such as rheumatic fever. This is supported by Harrison 21e Ch 70 and is the standard of care for streptococcal-triggered guttate psoriasis. ## Why each distractor is wrong - **Immediate tonsillectomy**: While tonsillectomy may benefit patients with recurrent streptococcal-triggered guttate psoriasis (as shown in the PALMA trial), it is not the initial management. It is reserved for recurrent cases after antibiotic therapy has been attempted and streptococcal infection is confirmed to be the persistent trigger. - **Systemic methotrexate as first-line**: Systemic agents like methotrexate are reserved for severe or refractory guttate psoriasis. First-line topical therapy (medium-potency corticosteroids) and treatment of the streptococcal trigger are preferred initially. Methotrexate is not indicated in this acute presentation. - **Oral retinoids**: Oral retinoids have limited use in psoriasis management and are not first-line for guttate psoriasis. They are not appropriate as initial therapy, especially when the streptococcal trigger can be directly addressed with antibiotics. **High-Yield:** Guttate psoriasis triggered by streptococcal pharyngitis requires antibiotic therapy (penicillin V or amoxicillin × 10 days) as the cornerstone of initial management to address the trigger and prevent complications. [cite: Harrison 21e Ch 70]