What are the next steps for an 18-year-old female who developed a head-to-toe red itchy rash after finishing a 2-day course of Augmentin (amoxicillin-clavulanate) for E. coli and group B strep?

Management of Suspected Amoxicillin-Clavulanate Allergy

Immediately discontinue Augmentin and initiate symptomatic treatment with oral antihistamines and topical corticosteroids for this likely delayed-type hypersensitivity reaction. 1

Immediate Clinical Actions

Discontinue the Culprit Drug

• Stop Augmentin permanently – this head-to-toe pruritic rash appearing 2 days after completing the course represents a classic delayed-type (non-immediate) hypersensitivity reaction to amoxicillin-clavulanate. 2, 3
• The temporal relationship (onset >1 hour after last dose, specifically 2 days post-completion) definitively classifies this as a delayed reaction rather than immediate IgE-mediated hypersensitivity. 2, 4

Symptomatic Management

• Prescribe oral antihistamines (e.g., cetirizine 10mg daily or diphenhydramine 25-50mg every 6 hours) to control pruritus. 3
• Apply topical hydrocortisone 1% cream to affected areas 3-4 times daily as needed for itch relief. 5
• Monitor closely for progression to severe cutaneous adverse reactions (Stevens-Johnson syndrome, toxic epidermal necrolysis) – specifically watch for mucosal involvement, blistering, skin sloughing, or systemic symptoms. 3

Critical Assessment for Severity

Rule Out Severe Reactions

• Examine for warning signs: purple bullae, skin sloughing, mucosal involvement (oral, ocular, genital), facial edema, or systemic toxicity (fever, hypotension). 1, 3
• If any severe features present, this requires immediate emergency department evaluation and possible hospitalization. 3
• This patient's presentation (pruritic rash only, no other symptoms) suggests a benign delayed maculopapular exanthem rather than a severe cutaneous adverse reaction. 1, 2

Documentation and Allergy Labeling

Proper Documentation Requirements

• Document the following in the medical record: 1
  • Specific antibiotic: amoxicillin-clavulanate (Augmentin)
  • Type of reaction: delayed-type hypersensitivity (non-immediate)
  • Severity: non-severe (pruritic maculopapular rash without systemic symptoms)
  • Timing: 2 days after completion of therapy
  • Management: drug discontinued, symptomatic treatment initiated

Allergy Label Placement

• Add "amoxicillin-clavulanate allergy" to all medical records, electronic health systems, and provide the patient with written documentation. 1
• Specifically label this as a delayed, non-severe reaction to guide future antibiotic selection. 1

Future Antibiotic Selection

Immediate Alternatives

• For future infections requiring antibiotics, avoid all amoxicillin-containing products (amoxicillin, amoxicillin-clavulanate). 1
• Cephalosporins with dissimilar R1 side chains are safe alternatives – avoid ceftriaxone, cefotaxime, cefpodoxime (which share R1 side chains with amoxicillin), but cephalexin, cefuroxime, cefdinir, or cefprozil can be used safely. 1
• Macrolides (azithromycin, clarithromycin) are appropriate alternatives for respiratory or soft tissue infections in penicillin-allergic patients. 6
• Fluoroquinolones or trimethoprim-sulfamethoxazole are additional options depending on the infection type. 1

Consideration for Future Delabeling

• This patient may be eligible for delabeling after >1 year since the Dutch guidelines suggest patients with non-severe delayed reactions occurring >1 year ago can receive the culprit beta-lactam without formal testing. 1
• However, given the recent nature of this reaction, avoid re-exposure for at least 1 year. 1
• If amoxicillin is critically needed in the future (>1 year from now), she could potentially undergo supervised rechallenge or formal allergy testing, though this is rarely necessary given available alternatives. 1

Common Pitfalls to Avoid

• Do not assume this represents true IgE-mediated allergy – delayed rashes are often T-cell mediated and have different cross-reactivity patterns than immediate reactions. 2, 4
• Do not avoid all beta-lactams unnecessarily – this patient can safely receive most cephalosporins and carbapenems based on side-chain differences. 1
• Do not rechallenge within 1 year – the risk of reaction remains elevated during this period for delayed-type reactions. 1
• Ensure the allergy label specifies "delayed, non-severe" rather than just "penicillin allergy" to prevent unnecessary broad-spectrum antibiotic use in the future. 1