How long after commencing oral penicillin (Penicillin) does the rash in Scarlet fever resolve?

Medical Advisory BoardAll articles are reviewed for accuracy by our Medical Advisory Board
Educational purpose only • Exercise caution as content is pending human review
Article Review Status
Submitted
Under Review
Approved

Last updated: April 26, 2025View editorial policy

Personalize

Help us tailor your experience

Which best describes you? Your choice helps us use language that's most understandable for you.

From the Guidelines

The rash in scarlet fever typically begins to fade within 2-3 days after starting oral penicillin treatment, with complete resolution usually occurring within 7 days. When treating scarlet fever with oral penicillin, it is essential to consider the guidelines for the management of Group A Streptococcal infections, as outlined in the 2012 update by the Infectious Diseases Society of America 1. The standard treatment approach includes a 10-day course of oral penicillin, which is crucial for ensuring the eradication of the causative organism from the pharynx, usually within 10 days, as per the guideline recommendations 1. Key points to consider in the management of scarlet fever include:

  • Completing the full course of antibiotics, even if symptoms improve earlier, to prevent recurrence and reduce the risk of complications
  • Monitoring for signs of improvement, such as reduction in fever and rash, within 3-4 days of starting antibiotics
  • Being aware of potential antibiotic resistance or alternative diagnoses if the rash does not improve or if fever persists beyond 48 hours of treatment
  • The typical dosing regimen for oral penicillin V (phenoxymethylpenicillin) is 250-500 mg two to four times daily for adults, or 25-50 mg/kg/day divided into doses for children. During recovery, patients often experience peeling of the skin, particularly on the fingertips, toes, and groin area, as the rash resolves and the skin heals.

From the Research

Duration of Rash in Scarlet Fever after Commencing Oral Penicillin

  • The provided studies do not directly address the duration of the rash in scarlet fever after commencing oral penicillin.
  • However, the studies suggest that oral penicillin is an effective treatment for scarlet fever, and it can help reduce the risk of complications and the spread of infection 2, 3.
  • The studies also discuss the epidemiology and antimicrobial resistance of group A Streptococcus, the bacteria that causes scarlet fever, but they do not provide information on the specific duration of the rash after treatment 4, 5, 6.
  • Therefore, there is no direct evidence from the provided studies to answer the question of how long after commencing oral penicillin the rash in scarlet fever goes away.

References

Guideline

Guideline Directed Topic Overview

Dr.Oracle Medical Advisory Board & Editors, 2025

Research

Scarlet fever: a guide for general practitioners.

London journal of primary care, 2017

Research

Managing scarlet fever.

Drug and therapeutics bulletin, 2017

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

Have a follow-up question?

Our Medical A.I. is used by practicing medical doctors at top research institutions around the world. Ask any follow up question and get world-class guideline-backed answers instantly.