What testing and referrals are recommended for a patient in primary care following hospitalization for new anaphylaxis due to an antibiotic?

From the Guidelines

For a patient in primary care following hospitalization for new anaphylaxis due to an antibiotic, I recommend immediate referral to an allergist/immunologist for comprehensive evaluation and management. The primary care provider should ensure the patient has been prescribed an epinephrine auto-injector (such as EpiPen or Auvi-Q 0.3mg for adults, 0.15mg for children weighing 15-30kg) and educated on its proper use, as emphasized by the guidelines for anaphylaxis management 1. The patient should carry two auto-injectors at all times and replace them before their expiration date. Documentation of the antibiotic reaction should be prominent in the medical record, with clear alerts in the electronic health record system. The patient should be provided with medical alert identification (bracelet or card) specifying their antibiotic allergy.

While awaiting specialist evaluation, alternative antibiotics from different classes should be used if infection treatment is needed. The allergist will likely perform skin testing and possibly graded drug challenges to confirm the specific antibiotic allergy and identify safe alternatives, as outlined in the practice parameters for the diagnosis and management of anaphylaxis 1. This referral is crucial because antibiotic allergies can be complex, with potential cross-reactivity between related medications, and proper evaluation can prevent both future anaphylaxis and unnecessary restriction of potentially useful antibiotics. The primary care provider should also assess for and address any comorbidities that might complicate anaphylaxis management, such as asthma, cardiovascular disease, or use of beta-blockers or ACE inhibitors, considering the recommendations for consultation with an allergist-immunologist 1.

Key considerations in the management of these patients include:

• Ensuring access to epinephrine auto-injectors and proper education on their use
• Providing medical alert identification
• Documenting the antibiotic allergy clearly in the medical record
• Considering alternative antibiotics when necessary
• Referring to an allergist/immunologist for comprehensive evaluation and management, especially given the potential complexity of antibiotic allergies and the need for specialized care to prevent future episodes of anaphylaxis, as highlighted in the guidelines 1.

From the Research

Testing for Anaphylaxis

• Patients who have experienced anaphylaxis due to an antibiotic should undergo testing to confirm the allergy and identify the specific antibiotic responsible 2, 3.
• Penicillin allergy skin testing is a simple and effective way to identify true penicillin allergy, and should be conducted in a facility with available life-support equipment 2.
• Skin testing involves testing for both major and minor determinants, and alternatives to skin testing include laboratory synthesis of major determinants, use of the radioallergosorbent test (RAST), or a combination of RAST and minor determinant skin testing 2.
• For patients with a history of anaphylactic reaction to penicillin, skin tests including immediate patch test (IPT), skin prick test (SPT), or intradermal test (IT) with penicillin G can be used to diagnose penicillin allergy 3.

Referrals

• Patients who have experienced anaphylaxis due to an antibiotic should be referred to an allergist or immunologist for further evaluation and testing 2, 4.
• Referral to a specialist is particularly important for patients who require antibiotic therapy, as they may need to undergo desensitization or be treated with alternative antibiotics 2, 4.
• Patients with a history of anaphylactic reactions to antibiotics should also be educated on how to recognize and respond to anaphylaxis, and should carry an epinephrine auto-injector with them at all times 5, 6.

Additional Considerations

• When taking a patient's medical history, it is essential to consider the possibility of antibiotic allergy and to ask specific questions about previous reactions to antibiotics 5, 6.
• A thorough medical history and physical examination are crucial in diagnosing and managing antibiotic allergies, and can help to identify patients who are at risk of anaphylaxis 6.
• In cases where anaphylaxis is suspected, prompt treatment with epinephrine, antihistamines, and corticosteroids is essential, and patients should be monitored closely for signs of respiratory distress or cardiovascular collapse 4, 6.