What to do for a patient with urticaria and lip swelling after starting Augmentin (amoxicillin/clavulanate) for a dental infection following wisdom teeth extraction?

Immediate Management of Suspected Augmentin Allergy

Stop Augmentin immediately and do not rechallenge—this patient is experiencing a drug hypersensitivity reaction with urticaria and angioedema, which are contraindications to further beta-lactam use. 1

Acute Treatment Protocol

First-Line Medications (Administer Now)

• Administer a second-generation H1 antihistamine: Cetirizine 10 mg PO/IV or loratadine 10 mg PO for urticaria control 2
• Add corticosteroid: Hydrocortisone 200 mg IV (or equivalent oral prednisone) to prevent progression and reduce inflammation 2
• Apply white soft paraffin ointment to lips every 2 hours to protect and moisturize the swollen lip tissue 2, 3

Avoid These Common Errors

• Do NOT give diphenhydramine (first-generation antihistamine) as it can paradoxically worsen hypotension, cause tachycardia, and mask progression of symptoms 2
• Do NOT use vasopressors unless true anaphylaxis develops with severe hypotension unresponsive to IV fluids 2

Monitoring Requirements

• Observe for at least 4 hours after symptom resolution to watch for biphasic reactions, which can occur up to 6 hours later 2
• Monitor vital signs every 15 minutes initially, including blood pressure, pulse, and oxygen saturation 2
• Watch for progression to anaphylaxis: respiratory symptoms (wheezing, stridor, dyspnea), severe hypotension (SBP <100 mmHg), or gastrointestinal symptoms 2

Discharge Planning

Medications to Prescribe

• Long-acting oral antihistamine: Cetirizine 10 mg daily or loratadine 10 mg daily for 3-5 days, as urticaria may recur over 1-2 days after drug reactions 2
• Prednisone taper: 40-60 mg daily for 3 days, then taper over 5-7 days to prevent delayed reactions 2
• Epinephrine auto-injector: Prescribe for emergency use if symptoms worsen or recur 2

Critical Patient Instructions

• Document penicillin/beta-lactam allergy in medical records permanently—this includes amoxicillin, ampicillin, penicillin, and cephalosporins 1
• Avoid all beta-lactam antibiotics (penicillins and cephalosporins) due to cross-reactivity risk 2, 1
• Seek emergency care immediately if experiencing difficulty breathing, throat tightness, dizziness, or worsening swelling 2

Alternative Antibiotic for Dental Infection

For Penicillin-Allergic Patients

• Clindamycin 300 mg PO three times daily for 7-10 days is the preferred alternative for odontogenic infections in penicillin-allergic patients 2
• Alternative option: Azithromycin 500 mg on day 1, then 250 mg daily for days 2-5 2

Supportive Oral Care

• Clean mouth daily with warm saline mouthwashes to reduce bacterial load and promote healing 2, 3
• Use benzydamine hydrochloride oral rinse every 3 hours for pain control, particularly before eating 2, 3
• Apply antiseptic oral rinse (0.2% chlorhexidine) twice daily to prevent secondary infection 2

Follow-Up Requirements

• Return in 24-48 hours to assess resolution of urticaria and lip swelling 2
• Allergy testing referral: Consider referring to allergist for formal penicillin allergy testing once acute reaction resolves (wait at least 4-6 weeks) 2
• If symptoms persist beyond 2 weeks, reevaluate for alternative diagnoses such as angioedema without wheals or urticarial vasculitis 2

Red Flags Requiring Immediate Emergency Care

• Respiratory compromise: Stridor, wheezing, difficulty breathing, or oxygen saturation <92% 2
• Cardiovascular instability: Systolic blood pressure <90 mmHg despite IV fluids 2
• Rapid progression: Symptoms worsening despite treatment within 15 minutes 2
• Tongue or throat swelling causing difficulty swallowing or speaking 2