What is the best initial treatment for a patient with pollen allergy presenting with cough and shortness of breath (SOB) upon coughing, considering dexamethasone (IM)?

Treatment of Pollen Allergy with Cough and Shortness of Breath

No, you should not administer intramuscular dexamethasone as initial therapy for this patient—this presentation meets criteria for anaphylaxis and requires immediate intramuscular epinephrine as first-line treatment. 1

Immediate Assessment for Anaphylaxis

Your patient meets anaphylaxis diagnostic criteria based on the following: 1

• Sudden respiratory symptoms (cough causing shortness of breath) after exposure to a likely allergen (pollen)
• This fulfills criterion #2: two or more organ systems involved suddenly after allergen exposure 1

Epinephrine 0.01 mg/kg of a 1:1000 (1 mg/mL) solution intramuscularly in the anterolateral thigh is the only appropriate first-line treatment, with maximum doses of 0.5 mg (adult) or 0.3 mg (child). 1

Why Dexamethasone IM is NOT Appropriate First-Line

• There are no absolute contraindications to epinephrine in anaphylaxis, and the risk of death from untreated anaphylaxis outweighs concerns about epinephrine side effects 1
• Corticosteroids like dexamethasone have no role in acute anaphylaxis management and do not reverse life-threatening symptoms 1
• While corticosteroids may help prevent biphasic reactions, they should only be given after epinephrine 1
• The FDA-approved dosing for dexamethasone IM (0.5-9 mg/day) is intended for chronic inflammatory conditions, not acute allergic emergencies 2

Immediate Management Algorithm

1. Administer epinephrine IM immediately in the anterolateral thigh; repeat every 5-15 minutes if needed 1
2. Position patient supine with legs elevated (standing suddenly can cause fatality) 1
3. Give supplemental oxygen at 6-8 L/minute by face mask 1
4. Establish IV access with large-bore cannula (14-16 gauge) and give 1-2 liters of normal saline rapidly (5-10 mL/kg in first 5-10 minutes for adults, 10 mL/kg for children) 1
5. Monitor for incomplete response to epinephrine, which indicates need for large-volume fluid resuscitation 1

If This is NOT Anaphylaxis

If upon reassessment the patient has isolated cough without true shortness of breath or other systemic symptoms, then this represents allergic rhinitis with post-nasal drip causing cough (upper airway cough syndrome): 1

• First-line treatment: First-generation antihistamine plus decongestant (e.g., dexbrompheniramine 6 mg BID or azatadine 1 mg BID plus pseudoephedrine 120 mg BID) 1
• Alternative options: Nasal corticosteroids, nasal antihistamines, or oral leukotriene inhibitors 1
• Expected response time: Some improvement within days to 1-2 weeks; complete resolution may take several weeks 1

In this scenario, oral or intranasal corticosteroids would be appropriate, but IM dexamethasone still has no role 1, 2

Critical Pitfall to Avoid

Do not confuse allergic rhinitis with cough for anaphylaxis. The key distinguishing feature is whether the patient has true dyspnea/shortness of breath (anaphylaxis) versus cough alone from post-nasal drip (upper airway cough syndrome). 1 Your description of "SOB when cough" suggests respiratory compromise, which mandates treating as anaphylaxis until proven otherwise. 1