Macrolide allergy: which tests are really useful?

Acute allergic reaction caused by topical azithromycin eye drops: A report of two cases

Azithromycin 1.5% ophthalmic solution (Azyter®, Thea Pharmaceuticals, Newcastle, UK) is an effective and well-tolerated option for the treatment of bacterial conjunctivitis and blepharitis, and has the advantage of a shorter treatment duration than other topical antibiotics. No acute allergic reaction has yet been reported in response to topical azithromycin eye drops. Here, we report two cases with unusual acute-type allergic reaction to topical azithromycin eye drops. A 63-year-old female patient and 67-year-old male patient treated for blepharitis with topical azithromycin 1.5% eye drops presented with epiphora, eyelid edema, chemosis, conjunctival injection, hyperemia, intensive papillary reaction, and rhinitis within 30 min of instillation. Upon cessation of the topical medication and administration of antiallergic therapy, both patients immediately showed dramatic improvement. Acute-type allergic reaction to topical azithromycin eye drops may be a rare side effect, but ophthalmologists should keep this possibility in mind and inform the patients about its potential occurrence.

[Allergies to antibiotic drugs: their importance in otorhinolaryngology]

BACKGROUND

In 2009, over 40 million prescriptions for antibiotic drugs were counted in outpatient medical care in Germany. This represents a turnover of more than 750 million euros. With over 80 million daily defined doses (DDD), amoxicillin was the most frequently prescribed antibiotic in Germany in 2008. Given the average of 5775 DDD per doctor, otolaryngologists prescribed more antibiotics than specialists in any other field of medicine in 2008; approximately 82% of these were β-lactams and tetracyclines.

MATERIAL AND METHODS

This article is based on selective literature-based research using the PubMed database. The keywords used in the search were:"allergy","anaphylaxis" and"hypersensitivity", in combination with "penicillin","cephalosporin","carbapenem","cotrimoxazole","macrolide","aztreonam" and"tetracycline".

RESULTS

Allergic reactions to antibiotics are among the most frequently reported adverse side effects arising from drug treatment. However, non-allergic adverse side effects owing to drug intolerance are also very common and may be clinically indistinguishable from allergic reactions. Owing to a frequent lack of appropriate diagnostic investigation, the decision to withhold effective standard treatments from patients is often based solely upon anamnestic observations. Up to 10% of respondents in an unselected population report an allergy to penicillin. In 80% of these cases, however, no penicillin-specific IgE-antibodies can be detected.

CONCLUSION

A detailed understanding of the symptoms, diagnostic options and possible cross reactions pertaining to allergic reactions to antibiotics, as well to non-allergic adverse side effects with similar clinical appearance, is very important for otolaryngologists. This profound knowledge ensures that the correct diagnostic steps are taken and that appropriate treatment decisions prevent the unnecessary use of reserve antibiotics.