Treatment of Urticaria in Pregnancy

General Approach to Antihistamines in Pregnancy

• The British Journal of Dermatology recommends that when urticaria treatment is necessary during pregnancy, second-generation antihistamines—specifically cetirizine or loratadine—should be used as they are FDA Pregnancy Category B drugs with the best safety profile 1, 2, 3
• Ideally, all antihistamines should be avoided during pregnancy, especially in the first trimester, though none has been proven teratogenic in humans 1, 2, 3
• Hydroxyzine is specifically contraindicated during early pregnancy and should never be used 1, 2, 3

First-Line Treatment Algorithm

• Cetirizine and loratadine are the antihistamines of choice as FDA Pregnancy Category B drugs, meaning no evidence of fetal harm exists though controlled human studies are lacking 1, 2, 3
• Chlorphenamine is often selected by UK clinicians when antihistamine therapy is necessary due to its long safety record, despite being a first-generation antihistamine 1, 2, 3

Dosing Strategy

• Start with standard doses of the chosen antihistamine 2, 3, 4
• If symptom control is inadequate after 2-4 weeks, consider increasing the dose up to 4 times the standard dose, weighing potential benefits against risks 2, 3, 4

Second-Line Treatment: Omalizumab

• Standard dosing is 300 mg every 4 weeks 2, 3, 4
• Allow up to 6 months to evaluate response before considering alternatives 2, 3, 4

Corticosteroids: Use Sparingly

• Limit oral corticosteroids to short courses (3 days) only for severe acute exacerbations 1, 2
• Short tapering courses over 3-4 weeks may be necessary for severe cases, but long-term use should be avoided 1
• Use lower doses than standard adult dosing when possible 2

Medications to Avoid During Pregnancy

• Hydroxyzine is contraindicated in early pregnancy 1, 2, 3
• First-generation antihistamines other than chlorphenamine should generally be avoided due to sedating effects, though chlorphenamine itself is acceptable 1

Critical Safety Considerations

• Intramuscular epinephrine remains life-saving for anaphylaxis or severe laryngeal angioedema even during pregnancy 1, 2
• Dosing: 0.5 mL of 1:1000 (500 µg) for adults and adolescents over 12 years 1, 2
• Fixed-dose epinephrine auto-injectors (300 µg) should be prescribed for patients at risk of life-threatening attacks 2, 4

Adjunctive Measures

• Identify and minimize aggravating factors including overheating, stress, alcohol, and certain medications (aspirin, NSAIDs, codeine) 2, 3, 4
• Cooling antipruritic lotions (calamine or 1% menthol in aqueous cream) provide symptomatic relief without systemic absorption 2, 3

Treatment of Itching and Hives in Early Pregnancy

Adjunctive Non-Pharmacologic Measures

• The British Association of Dermatologists recommends using emollients to prevent skin dryness, avoiding hot baths or showers, and keeping nails shortened to minimize scratching, as part of a comprehensive approach to managing itching and hives in early pregnancy 5

Corticosteroids: Use Only for Severe Acute Exacerbations

• The British Association of Dermatologists suggests that prednisolone is preferred over other corticosteroids for severe acute exacerbations because it is 90% inactivated by the placenta, minimizing fetal exposure 6

Common Pitfalls to Avoid

• The American Academy of Allergy, Asthma, and Immunology advises against using diphenhydramine as first-line treatment due to its association with cleft palate development, despite its frequent use during pregnancy 7
• The American Academy of Allergy, Asthma, and Immunology recommends avoiding oral decongestants during the first trimester due to conflicting reports of associations with gastroschisis and small intestinal atresia 7

Management Strategies for Acute Urticaria in Pregnancy

Dose Escalation of Second‑Generation Antihistamines

• If standard dosing does not achieve adequate symptom control after 2–4 weeks, the antihistamine dose may be increased up to four‑fold (e.g., cetirizine 40 mg daily or loratadine 40 mg daily), with careful weighing of potential maternal benefit against fetal risk. 8
• Dose escalation may be initiated earlier when symptoms are intolerable to the patient. 8

Short‑Course Systemic Corticosteroids for Severe Exacerbations

• Oral prednisolone is preferred for short‑term (3‑day) treatment of severe acute urticaria because approximately 90 % of the drug is inactivated by the placenta, thereby limiting fetal exposure. 9

Omalizumab as Second‑Line Therapy

• For cases refractory to antihistamines, subcutaneous omalizumab 300 mg every 4 weeks can be considered, acknowledging that pregnancy‑specific safety data are limited. 8
• A treatment trial of up to 6 months should be allowed to assess clinical response before switching to alternative therapies. 8

Safety of Antihistamines and Adjunct Therapies in First‑Trimester Pregnancy

Antihistamine Safety

• Loratadine’s safety profile is comparable to cetirizine, as affirmed by the European Respiratory Society and multiple allergy guideline societies (observational safety data; moderate‑level evidence) 10.

Biologic Therapy (Omalizumab)

• First‑trimester exposure to omalizumab does not increase adverse pregnancy outcomes compared with other pregnant women who have moderate‑to‑severe disease, according to the EXPECT registry (prospective cohort; moderate‑level evidence) 10.

• Monoclonal antibodies cross the placenta increasingly as pregnancy progresses; therefore, first‑trimester exposure to omalizumab carries less theoretical fetal risk than exposure in later trimesters (pharmacokinetic data; low‑level mechanistic evidence) 10.

Systemic Corticosteroid Risks

• Systemic corticosteroid use in the first trimester is associated with a three‑fold increased risk of isolated cleft lip ± cleft palate, although the therapeutic benefit in severe disease may outweigh this risk (observational case‑control data; moderate‑level evidence) 10.