Clinical history for initial assessment of patients reporting antimicrobial hypersensitivity
Clinical history is critically important in the diagnosis of antimicrobial hypersensitivity. If hypersensitivity is reported, see Questions to ask patients reporting an antimicrobial allergy in an antimicrobial allergy assessment for questions to ask the patient.
Validated tools are available for the initial assessment of patients reporting penicillin hypersensitivity (see Clinical history for initial assessment of patients reporting penicillin hypersensitivity) and trimethoprim+sulfamethoxazole hypersensitivity (see Clinical history for initial assessment of adults reporting trimethoprim+sulfamethoxazole hypersensitivity).
Common predictable adverse reactions to antimicrobials include gastrointestinal reactions (eg nausea, vomiting, diarrhoea), neurological effects (eg headache, dizziness) and skin effects (eg pruritus without rash, fever or internal organ involvement). In many cases these reactions do not justify avoiding the antimicrobial in future.
A family history of antimicrobial allergy does not justify avoidance of the implicated drug.
If clinical history suggests that the reported reaction is a drug intolerance (eg gastrointestinal disturbance) rather than a hypersensitivity reaction, direct delabeling (ie removal of a patient’s reported antibiotic allergy based on their history alone) of the patient’s allergy is appropriate.
Severity and type of reaction
Do you remember the details of the reaction?
How was the reaction managed? Did it require treatment or hospitalisation?
Timing
How long after taking the antibiotic did the reaction occur?
How many years ago did the reaction occur?
Antibiotic use since reaction
Are there other antibiotics that you have taken without problems since the reaction?