Can you have an allergic reaction to hydroxyzine?

Allergic Reactions to Hydroxyzine

Yes, you can definitely have an allergic reaction to hydroxyzine, despite it being an antihistamine medication commonly used to treat allergic reactions. 1, 2

Types of Allergic Reactions to Hydroxyzine

Hydroxyzine can cause several types of hypersensitivity reactions:

• Cutaneous reactions:

  • Generalized maculopapular eruptions 3
  • Urticaria/angioedema 2
  • Contact dermatitis 4
  • Fixed drug eruptions 2
  • Acute Generalized Exanthematous Pustulosis (AGEP) - a serious skin reaction characterized by fever and numerous small, superficial pustules 1

• Systemic reactions:

  • Anaphylaxis (rare but documented) 2

Risk Factors and Cross-Reactivity

• Previous sensitization to hydroxyzine or chemically related compounds 3

• Cross-reactivity with:

  • Cetirizine (a metabolite of hydroxyzine) 5
  • Ethylenediamine compounds 4
  • Piperazine derivatives 5

• Patients who have experienced AGEP or other hypersensitivity reactions with hydroxyzine should avoid cetirizine or levocetirizine due to cross-sensitivity risk 1

Clinical Presentation

• Onset varies from minutes (anaphylaxis, urticaria) to hours (maculopapular rashes) or longer (contact dermatitis) 2
• Symptoms may mimic the condition being treated, making diagnosis challenging 2
• No correlation exists between subjective symptoms and objective performance impairment 6

Management of Hydroxyzine Allergic Reactions

1. Immediate discontinuation of hydroxyzine at the first sign of skin rash or hypersensitivity 1

2. For mild reactions:

   • Discontinue the medication
   • Consider non-sedating H1 antihistamines like cetirizine 10mg, loratadine 10mg, or fexofenadine 180mg (unless cross-reactivity is suspected) 7

3. For severe reactions:

   • Standard anaphylaxis protocol including epinephrine, oxygen, antihistamines, and corticosteroids 8
   • Seek immediate medical attention

4. Alternative medications:

   • Consider SSRIs or SNRIs for long-term anxiety management 7
   • Buspirone may be a safer alternative for anxiety treatment 7
   • For pruritus, consider second-generation antihistamines or other treatment options 7

Prevention

• Challenge testing with multiple preparations may identify tolerable alternatives 2
• Avoid all potentially cross-reactive medications in patients with confirmed hydroxyzine allergy 1
• Patients with hydroxyzine allergy should inform all healthcare providers about their allergy

Important Considerations

• Diagnosis is primarily based on clinical suspicion and may be verified by challenge testing 2
• Patch testing may be useful in cases of contact dermatitis or fixed drug eruptions 2
• The causal relationship can be difficult to recognize as the reaction may mimic the condition being treated 2

Although hydroxyzine is an antihistamine used to treat allergic reactions, it can paradoxically cause allergic reactions in sensitive individuals. Prompt recognition and discontinuation of the medication are essential to prevent progression to more severe reactions.