Management of Acute Urticaria in Pregnancy
Second-generation H1 antihistamines are the first-line treatment for acute urticaria in pregnant patients, with loratadine being an appropriate choice after consulting a healthcare professional, as recommended by FDA labeling. 1
Initial Assessment and Diagnosis
- Acute urticaria is diagnosed clinically based on history and physical examination; routine laboratory testing is unnecessary unless specific triggers are suspected 2, 3
- Individual wheals resolve within 2-24 hours without scarring, distinguishing ordinary urticaria from urticarial vasculitis where lesions persist for days 3
- Document recent exposures to common triggers including foods, medications (especially aspirin and NSAIDs), infections, and physical factors 3, 4
First-Line Pharmacologic Treatment
- Non-sedating H1 antihistamines constitute the cornerstone of therapy 2, 3
- Loratadine specifically requires consultation with a healthcare professional before use in pregnancy per FDA labeling 1
- Offer at least two different non-sedating H1 antihistamine options, as individual responses and tolerance vary 2
- Standard dosing should be used initially; dose escalation up to 4-fold may be considered if inadequate response, though this practice is off-label 2, 5
Adjunctive Measures
Non-Pharmacologic Management
- Apply cooling antipruritic lotions such as calamine or 1% menthol in aqueous cream for symptomatic relief 2
- Minimize aggravating factors including overheating, stress, and alcohol 2, 3
- Avoid aspirin and NSAIDs as they can trigger mast cell degranulation and worsen urticaria 2, 3, 5
Short-Course Corticosteroids
- A brief course of oral corticosteroids may shorten episode duration in severe cases 3
- Long-term oral corticosteroids should NOT be used except in very selected cases under regular specialist supervision 2, 3
- The benefit of systemic steroids in acute urticaria is limited, and they may cause unnecessary morbidity 6
Emergency Management
Life-Threatening Presentations
- Intramuscular epinephrine is life-saving in anaphylaxis and severe laryngeal angioedema 2, 3
- Administer 0.5 mL of 1:1000 (500 µg) epinephrine intramuscularly for adults 2
- If no significant relief after the first dose, give a second dose 2, 3
- Use epinephrine with caution in patients with hypertension or ischemic heart disease 2
- Consider prescribing an epinephrine autoinjector for home use if the patient is at risk of recurrent life-threatening attacks 2, 3
Important Caveats and Pitfalls
What NOT to Do
- Do not perform extensive laboratory workups for typical acute urticaria—they add no clinical value 3
- Do not prescribe epinephrine autoinjectors for routine acute urticaria without evidence of anaphylaxis 6
- Avoid ACE inhibitors if angioedema is present, as they can worsen angioedema without wheals 2, 5
When to Suspect Alternative Diagnoses
- Wheals persisting beyond 24 hours suggest urticarial vasculitis and require skin biopsy 2, 3
- Recurrent fever with urticaria should prompt consideration of autoinflammatory syndromes rather than ordinary urticaria 7
- Non-itchy angioedema without urticaria may represent bradykinin-mediated angioedema (hereditary or acquired), which does not respond to antihistamines, epinephrine, or corticosteroids 6