Intradermal skin test sensitivity and specificity were 75% and 90% in clarithromycin allergy

Clarithromycin is one of the frequently prescribed oral macrolidic antibiotics in the pediatric population (the chemical structure is shown on the right). Suspected adverse reactions to clarithromycin have been relatively often described by parents but there is a lack of reliable detection of specific IgE antibodies.

This Italian study investigated the prevalence of a clarithromycin allergy in children using standardized skin tests and oral provocation tests (OPTs).

64 children were referred with a history of a clarithromycin-associated adverse drug reaction. All these children underwent skin tests and OPTs. The nonirritating intradermal skin test concentration for clarithromycin was determined in a control group of 18 children who had tolerated clarithromycin in the previous month. The nonirritating intradermal concentration was 10:2 dilution (0.5 mg/mL).

9 of the 64 children had an immediately positive intradermal response to the 10:2 dilution and only 1 child to the 10:3 dilution (0.05 mg/mL). None had positive skin prick test results or delayed skin responses to intradermal tests. 4 of 64 children (6%) with previously described adverse reactions due to clarithromycin intake had a positive OPT reaction.

When the intradermal skin test was correlated to the OPT results, intradermal test sensitivity and specificity were 75% and 90%, respectively.

Intradermal tests seem to be useful in workup in children with suspected clarithromycin hypersensitivity and may help reduce the need for OPTs.


Classification of adverse reactions to drugs.


SOAP III mnemonic for classification of adverse reactions to drugs.

Nonirritant intradermal skin test concentrations of ciprofloxacin ~0.0067 mg/ml, clarithromycin ~0.05 mg/ml, rifampicin ~0.002 mg/ml. Allergy, 2012.


References:

Sensitivity and specificity of skin tests in the diagnosis of clarithromycin allergy. Ann Allergy Asthma Immunol. 2010 May;104(5):417-9. Mori F, Barni S, Pucci N, Rossi E, Azzari C, de Martino M, Novembre E.
Drug provocation tests remain the key to diagnosing macrolide allergy http://goo.gl/WM5rj
Pearls and Pitfalls of Allergen Testing - JCAAI http://goo.gl/6ThcC and http://goo.gl/Bfnhn
Image source: Clarithromycin structure, Wikipedia, public domain.

Twitter comments:

@AllergyNet: Macrolide antibiotic allergy: Which tests are really useful? http://j.mp/jAr3zV Bottom line: NONE (except challenge) Full PDF

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