What is the treatment for an Amoxicillin (amoxicillin) rash?

Treatment of Amoxicillin Rash

For most amoxicillin rashes, discontinuation of the medication and supportive care with antihistamines are the primary treatments, while severe reactions require immediate medical attention and may need corticosteroids. 1

Types of Amoxicillin Rashes and Their Management

Mild to Moderate Maculopapular Rash

• Most amoxicillin rashes are maculopapular, non-allergic reactions that resolve spontaneously within a few days without sequelae 2
• Treatment includes:
  • Discontinuation of amoxicillin if the rash is bothersome 1
  • Oral antihistamines (such as diphenhydramine or cetirizine) to reduce itching 1
  • Topical corticosteroids for localized symptoms 3
  • Acetaminophen or ibuprofen for associated fever or discomfort 4

Urticarial Rash (Hives)

• Urticarial reactions suggest a true allergic reaction and require more careful management 2
• Treatment includes:
  • Immediate discontinuation of amoxicillin 1
  • Oral antihistamines for symptom relief 1
  • Consider short course of oral corticosteroids for more severe cases 1
  • Avoidance of penicillins until allergy evaluation can be performed 5

Severe Cutaneous Adverse Reactions

• Amoxicillin can cause severe reactions including Stevens-Johnson syndrome (SJS), toxic epidermal necrolysis (TEN), and drug reaction with eosinophilia and systemic symptoms (DRESS) 1
• Management includes:
  • Immediate discontinuation of amoxicillin 1
  • Emergency medical attention 1
  • Supportive care, possibly including hospitalization 1
  • Systemic corticosteroids may be required 1

Special Considerations

Infectious Mononucleosis

• Patients with infectious mononucleosis have a 30-100% chance of developing a non-pruritic morbilliform rash when given amoxicillin 4
• This is not a true allergy but rather a unique interaction between the virus and medication 4
• These patients should not be permanently labeled as "penicillin allergic" 4
• They can typically take penicillins safely after the EBV infection resolves 4

Allergy Evaluation

• For patients with mild reactions, direct oral amoxicillin challenge without preliminary skin testing may be appropriate to confirm or rule out true allergy 6
• Studies show that 89% of children with reported penicillin allergy can have their allergy label removed after standardized oral challenges 7
• Patients with severe reactions (anaphylaxis, SJS, TEN) should avoid penicillins and undergo formal allergy evaluation 5

Algorithm for Management

1. Assess severity of the rash:

   • Mild maculopapular rash: Continue below
   • Urticaria or angioedema: Discontinue amoxicillin, treat with antihistamines 1
   • Severe reactions (mucosal involvement, blistering, skin detachment): Seek emergency care 1

2. For mild maculopapular rash:

   • If treating active infection: Consider switching to non-beta-lactam antibiotic 5
   • If symptoms are bothersome: Discontinue amoxicillin, provide symptomatic treatment 2
   • If minimal symptoms: May continue amoxicillin with close monitoring 2

3. Follow-up considerations:

   • Document reaction in medical record 5
   • Consider allergy consultation for clarification of true allergy status 5
   • For patients with infectious mononucleosis, note that rash is not a true allergy 4

Common Pitfalls and Caveats

• Many patients are incorrectly labeled as allergic to penicillin based on benign maculopapular rashes 2
• Overdiagnosis of penicillin allergies leads to use of less effective, broader-spectrum antibiotics 7
• The combination of allopurinol and amoxicillin increases the incidence of rashes compared to amoxicillin alone 1
• Patients with a history of severe reactions to penicillins may also react to cephalosporins 1
• Skin testing is neither required nor recommended to document the non-allergic basis of maculopapular amoxicillin rash 2