When should antihistamines (anti-allergic medications) be given to children?

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From the Guidelines

Antihistamines should be given to children when they experience mild allergic symptoms, such as a few hives or mild nausea/discomfort, after consulting with a healthcare provider. For children aged 2-5 years, common options include cetirizine (Zyrtec) at 2.5mg once daily or loratadine (Claritin) at 5mg once daily 1. Children 6-11 years can take cetirizine 5-10mg daily, loratadine 10mg daily, or fexofenadine (Allegra) 30mg twice daily. Older children (12+ years) typically receive adult dosing. Second-generation antihistamines like cetirizine, loratadine, and fexofenadine are preferred as they cause less drowsiness than first-generation options like diphenhydramine (Benadryl) 1. Always use children's formulations and measure doses accurately with the provided measuring device. Antihistamines work by blocking histamine receptors, preventing the chemical from triggering allergy symptoms.

  • Key considerations for antihistamine use in children include:
    • Consulting with a healthcare provider before administering antihistamines
    • Using second-generation antihistamines to minimize drowsiness and other side effects
    • Accurately measuring doses with the provided measuring device
    • Seeking emergency care immediately for severe allergic reactions involving breathing difficulties or significant swelling, as antihistamines alone are insufficient treatment 1. It is essential to note that antihistamines should not be used in place of epinephrine for severe allergic reactions, and parents and caregivers should be directed to use epinephrine autoinjectors for severe symptoms 1.

From the FDA Drug Label

In pediatric patients aged 2 to 5 years who received 5 mg of cetirizine, the mean Cmax was 660 ng/mL. In pediatric patients aged 6 to 23 months who received a single dose of 0. 25 mg/kg cetirizine oral solution (mean dose 2.3 mg), the mean Cmax was 390 ng/mL. The average AUC (O-t) in children 6 months to < 2 years of age receiving the maximum dose of cetirizine solution (2. 5 mg twice a day) is expected to be two-fold higher than that observed in adults receiving a dose of 10 mg cetirizine tablets once a day. Cetirizine hydrochloride at doses of 5 and 10 mg strongly inhibited the wheal and flare caused by intradermal injection of histamine in 19 pediatric volunteers (aged 5 to 12 years) and the activity persisted for at least 24 hours In a 35 day study in children aged 5 to 12, no tolerance to the antihistaminic (suppression of wheal and flare response) effects of cetirizine hydrochloride was found. In 10 infants 7 to 25 months of age who received 4 to 9 days of cetirizine in an oral solution (0. 25 mg/kg bid), there was a 90% inhibition of histamine-induced (10 mg/mL) cutaneous wheal and 87% inhibition of the flare 12 hours after administration of the last dose.

Antihistamines like cetirizine can be given to kids when they have allergic reactions.

  • The dosage for kids varies based on their age and weight.
  • For kids aged 6 to 23 months, a single dose of 0.25 mg/kg can be given.
  • For kids aged 2 to 5 years, a dose of 5 mg can be given.
  • For kids aged 6 to 11 years, doses of 5 to 10 mg can be given. It's always best to consult a doctor before giving any medication to kids. 2 2

From the Research

Antihistamine Use in Children

Antihistamines are commonly administered to children to treat symptoms of allergic diseases, such as rhinitis, asthma, urticaria, and anaphylaxis 3. The decision to give antihistamines to children depends on various factors, including the type of allergy, age, and medical history.

Types of Antihistamines

There are two main types of antihistamines: first-generation and second-generation. Second-generation antihistamines are preferred over first-generation antihistamines due to their better safety profile, including minimal cognitive and antimuscarinic side effects, and a longer duration of action 4.

Indications for Antihistamine Use

Antihistamines can be used to treat various allergic conditions in children, including:

  • Non-anaphylactic allergic reactions
  • Atopic eczema (AE)
  • Allergic rhinitis (AR) and conjunctivitis
  • Chronic spontaneous urticaria (CSU)
  • Intermittent and chronic cough
  • Anaphylaxis
  • Food protein-induced gastrointestinal allergy
  • Asthma prevention 4, 5

Safety and Tolerability

The safety and tolerability of antihistamines in children have been evaluated in several studies. Second-generation antihistamines, such as cetirizine, loratadine, and fexofenadine, have been found to be relatively safe and effective in reducing symptoms associated with allergic rhinitis in children 6, 5. However, first-generation antihistamines can cause adverse effects, such as sedation, cardiotoxicity, and impairment of psychomotor function 6, 7.

Age Considerations

The age of the child is an important consideration when prescribing antihistamines. For children under 2 years of age, many antihistamines are prescribed off-label, and there is a lack of data on drug safety in this age group 3. For children under 12 years of age, second-generation antihistamines, such as cetirizine, loratadine, and fexofenadine, are available and have been found to be safe and effective 6, 5.

Key Points to Consider

  • Antihistamines can be used to treat various allergic conditions in children
  • Second-generation antihistamines are preferred over first-generation antihistamines due to their better safety profile
  • The age of the child is an important consideration when prescribing antihistamines
  • Antihistamines should be used under the guidance of a healthcare professional, especially in children under 2 years of age 3, 4, 6, 5, 7

References

Guideline

Guideline Directed Topic Overview

Dr.Oracle Medical Advisory Board & Editors, 2025

Research

Antihistamines: ABC for the pediatricians.

Pediatric allergy and immunology : official publication of the European Society of Pediatric Allergy and Immunology, 2020

Research

Antihistamine use in children.

Archives of disease in childhood. Education and practice edition, 2015

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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