What is the next step in managing a patient with persistent cough, hives, and rash, who was initially treated for bronchitis (inflammation of the bronchial tubes) 2 weeks ago and has not shown improvement, and is now experiencing a rash and waking up with urticaria (hives) for the past 3 days without fever, following an initial sore throat?

Management of Persistent Post-Viral Cough with New-Onset Urticaria

Stop the antibiotic immediately and initiate treatment for both post-viral cough and acute urticaria, as the hives are most likely a drug reaction to the bronchitis treatment rather than part of the original illness. 1, 2

Immediate Actions

Discontinue the current antibiotic - The temporal relationship between antibiotic treatment for "bronchitis" and the development of hives 3 days ago strongly suggests a drug-induced urticarial reaction, which is a common adverse effect of antibiotics. 2

Assess for anaphylaxis - Ensure the patient has no signs of angioedema (lip/tongue swelling), respiratory distress, or hypotension that would require emergency treatment. 2

Treatment of Urticaria

Start a second-generation H1 antihistamine immediately as first-line therapy for acute urticaria:

• Options include cetirizine 10 mg daily, loratadine 10 mg daily, or fexofenadine 180 mg daily 2
• These can be titrated up to 4 times the standard dose if symptoms persist 2

Add adjunctive therapy if needed:

• H2 antihistamines (ranitidine or famotidine) can be added for refractory symptoms 2
• A brief corticosteroid burst (prednisone 40 mg daily for 3-5 days) may be considered if hives are severe or widespread 2
• Avoid first-generation antihistamines as primary therapy due to sedation, though they may be used adjunctively 2

Management of Persistent Cough

This is post-viral cough, not bacterial bronchitis - The 2-week duration following an upper respiratory infection with sore throat, absence of fever, and lack of improvement with antibiotics confirms this is subacute post-infectious cough (3-8 weeks duration), not bacterial infection. 1, 3

The productive phlegm does NOT indicate bacterial infection - Colored or purulent sputum simply reflects inflammatory cells and debris from viral infection and should not guide antibiotic decisions. 1, 3

Initiate appropriate symptomatic treatment:

• First-generation antihistamine plus decongestant (e.g., brompheniramine with sustained-release pseudoephedrine) to reduce cough severity and hasten resolution 1, 3
• NSAIDs such as naproxen may favorably affect cough 1, 3
• Honey, warm fluids, or simple linctuses for symptomatic relief 1
• Dextromethorphan 60 mg if cough is particularly distressing 1

Critical Diagnostic Considerations

Rule out cough-variant asthma - The persistent cough despite treatment raises the possibility of undiagnosed asthma or transient bronchial hyperresponsiveness following viral infection. 4

Consider empiric asthma trial if cough persists beyond 3 weeks:

• Inhaled corticosteroids plus short-acting beta-agonist 4
• This addresses both post-viral bronchial hyperresponsiveness and possible cough-variant asthma 4

Evaluate for upper airway cough syndrome (postnasal drip) - The initial sore throat and current productive cough suggest possible ongoing upper airway involvement requiring antihistamine/decongestant therapy. 4

Timeline and Follow-Up

Expect urticaria to resolve within days to 1 week after stopping the offending antibiotic and starting antihistamines. 2

Expect cough to improve within 2-4 weeks with appropriate symptomatic treatment, though complete resolution may take up to 8 weeks. 1

Reassess at 3 weeks if cough persists - Cough lasting beyond 3 weeks despite appropriate treatment requires systematic evaluation for other causes including asthma, GERD, or nonasthmatic eosinophilic bronchitis. 4, 1

Red flags requiring immediate re-evaluation:

• Development of fever, hemoptysis, weight loss, or night sweats 1
• New or worsening dyspnea or abnormal lung examination findings 1
• Cough persisting beyond 8 weeks (meets criteria for chronic cough requiring systematic workup) 4, 1

Common Pitfalls to Avoid

Do not continue or restart antibiotics - This patient has viral bronchitis with post-infectious cough, not bacterial infection, and antibiotics provide no benefit while increasing risk of adverse effects and resistance. 1, 3

Do not assume the rash is part of the viral illness - The temporal relationship (starting 3 days ago, 11 days after initial illness) strongly suggests drug reaction rather than viral exanthem. 2

Do not order chest X-ray unless red flags develop - In an otherwise healthy patient with normal vital signs, clear lung examination, and no fever, chest radiography is not indicated for subacute cough. 1, 3