Antihistamine Use in 2-Month-Old Infants
Antihistamines should generally NOT be given to a 2-month-old infant for routine allergic symptoms, as no antihistamine has FDA approval or established safety data for this age group. 1, 2
Critical Safety Considerations
The FDA and pediatric advisory committees recommend against using over-the-counter cough and cold medications, including first-generation antihistamines, in children below 6 years of age due to significant safety concerns. 3, 1 Between 1969 and 2006, there were 69 deaths associated with antihistamines in children under 6 years, with 41 cases occurring in children under 2 years. 1
First-Generation Antihistamines (Diphenhydramine, Chlorphenamine)
- Diphenhydramine was responsible for 33 deaths in children under 6 years and should be strictly avoided in this age group for routine allergic symptoms. 1, 2
- These medications lack proven efficacy in young children and carry risks of sedation, central nervous system toxicity, and overdose. 3, 4
Second-Generation Antihistamines
- Cetirizine is the only antihistamine with any safety data in infants, but this data only extends down to 6 months of age, not 2 months. 2, 5
- The studied dose for 6-11 month old infants was 0.25 mg/kg twice daily (mean daily dose 4.5 mg). 5
- Loratadine is only FDA-approved for children 2 years and older. 2, 6
- Fexofenadine, desloratadine, and levocetirizine lack safety data and FDA approval for infants under 2 years. 2
When Antihistamines Might Be Considered
In the rare emergency situation of anaphylaxis in a 2-month-old, diphenhydramine may be used as adjunctive therapy (never as first-line) at 1 mg/kg per dose (maximum 50 mg) in liquid oral formulation, but only under direct medical supervision. 1, 2 Epinephrine remains the only first-line treatment for anaphylaxis. 3
Clinical Pitfalls to Avoid
- Never use antihistamines "to make a child sleepy"—this is explicitly contraindicated per FDA labeling. 1, 2
- Do not use antihistamines to prevent wheezing or asthma in infants with atopic dermatitis or family history of allergy, as risks outweigh uncertain preventive benefits. 1, 2
- Many antihistamines are prescribed off-label in children younger than 2 years, which is precisely the age group where safety data are most lacking. 4
Recommended Approach
For a 2-month-old with suspected allergic symptoms, focus on identifying and avoiding triggers rather than pharmacotherapy. 3 If symptoms are severe enough to warrant treatment, immediate referral to a pediatric allergist is indicated rather than empiric antihistamine use. 3 The allergist can determine if treatment is truly necessary and, if so, provide appropriate monitoring for this vulnerable age group.