What is the dose of erythromycin (antibiotic) for a 13-year-old patient with Pityriasis Lichenoides Chronica (PLC)?

Erythromycin Dosage for Pityriasis Lichenoides Chronica in a 13-Year-Old Patient

For a 13-year-old patient with Pityriasis Lichenoides Chronica (PLC), the recommended dose of erythromycin is 30-50 mg/kg/day divided into four equal doses for at least 2-3 weeks. 1

Dosing Guidelines

• The FDA-approved erythromycin dosage for children is 30-50 mg/kg/day divided into equal doses, with the specific regimen depending on the severity of infection 1
• For skin conditions like PLC in pediatric patients, the standard dosing approach follows this general guideline, with treatment typically continuing for several weeks 2
• The dosing should be divided into four equal parts throughout the day to maintain therapeutic levels 1, 2

Treatment Duration

• Treatment should continue for at least 2-3 weeks, though some cases may require longer therapy 2, 3
• In a retrospective review of 124 pediatric PLC patients, erythromycin was administered to 79.7% of affected children, with 66.6% showing at least a partial response 2
• The average duration of PLC in pediatric patients is significantly longer than the acute form (PLEVA), with PLC lasting approximately 78 ± 48 months in some studies 4

Administration Considerations

• Erythromycin tablets are generally well absorbed and may be dosed without regard to meals 1
• However, optimal blood levels are obtained when erythromycin is given in the fasting state (at least 30 minutes and preferably 2 hours before meals) 1
• For children who have difficulty with tablets, erythromycin is available as oral suspension 1

Alternative Treatment Options

• If erythromycin is not effective or not tolerated, alternative treatments include:
  • Narrowband ultraviolet B phototherapy (effective in 88% of cases in some studies) 5
  • Azithromycin (has shown rapid response in some case reports) 6
  • Topical corticosteroids (27% response rate) 4
  • Heliotherapy (33% response rate) 4

Monitoring and Follow-up

• Regular follow-up is recommended to assess treatment response and adjust dosing if necessary 3
• Long-term follow-up is advised due to the chronic nature of PLC, with many patients experiencing recurrences 2, 4
• Monitor for common side effects of erythromycin including gastrointestinal disturbances 1

Clinical Pearls

• PLC tends to have a longer disease course compared to the acute form (PLEVA), with a median duration of 20 months in children 2
• The disease is often recurrent (77% of cases) and may show seasonal variation with onset most commonly in fall or winter 2
• Residual pigmentary changes may persist even after active inflammation resolves 4