Review Question - QID 105558

This patient has scarlet fever, for which the treatment of choice is penicillin. However, given the patient's previous reaction to penicillin administration, he should be treated with cephalexin (a first generation cephalosporin).

Scarlet fever is caused by infection with Group A Streptococcus (GAS) strains that produce erythrogenic exotoxins. Patients typically present with fever, an exudative pharyngitis, an erythematous sandpaper-like rash that classically starts on the neck and spreads to the trunk and face (with circumoral pallor), and strawberry tongue (Illustration A). Untreated scarlet fever may progress to cause purulent sinusitis, otitis media, or retropharyngeal or peritonsillar abscesses. Post infectious sequalae include acute rheumatic fever and post-streptococcal glomerulonephritis. Treatment of scarlet fever helps reduce the incidence of post-infectious complications. Patients with severe penicillin allergies (i.e. anaphylaxis or respiratory symptoms) should be treated with erythromycin or clindamycin to avoid the 10% cross-reactivity that occurs between penicillin and cephalosporins.

Hayes and Williamson review the management of GAS pharyngitis. They note that oral penicillin remains the preferred antibiotic for these infections, however patients with significant allergies often require alternative treatments.

Zwart et al. conducted a randomized trial of penicillin treatment duration. Neither three nor seven days of penicillin treatment had an effect on duration of symptoms, however penicillin treatment appeared to reduce the incidence of streptococcal sequelae.

Illustration A shows the classic "strawberry tongue" seen in patients with scarlet fever

Incorrect Answers:
Answer 1: The patient should not be desensitized to penicillin; cephalexin is the recommended treatment of choice for penicillin allergic patients.
Answer 2: Ceftriaxone (a third generation cephalosporin) has a broad spectrum of activity and would not be the antibiotic of choice for this patient.
Answer 3: Trimethoprim-sulfamethoxazole would not be the antibiotic of choice for this patient.
Answer 5: Ciprofloxacin (a fluoroquinolone) would not be the antibiotic of choice for this patient. Fluoroquinolones are rarely used in pediatric patients due to concern for tendonopathy.