Ünal D, et al. - The diagnostic value of in vivo tests in the diagnosis of hypersensitivity reactions (HRs) to macrolides was gauged, as well as, cross-reactivity between 4 different macrolides (clarithromycin, dirithromycin, spiramycin, and azithromycin) belonging to 3 different groups was appraised. Results highlighted DPT (Drug provocation test) as the only reliable method to predict macrolide hypersensitivity as well as to detect cross-reactivity between macrolides.

Methods

• For both the culprit and alternative macrolides, twenty-five patients with a history of immediate or delayed-type HRs to at least 1 macrolide and 20 healthy control subjects underwent skin testing.
• Further to this, all subjects underwent single-blind drug provocation tests (SBDPTs) with these drugs.

Results

• As per observations, twenty-one patients (84%) described an early reaction.
• On the other hand, the remaining 4 (16%) had delayed-type reactions.
• This study reported positive skin prick test results with culprit macrolides in only 2 patients who had experienced anaphylaxis.
• It was found that these 2 and another 4 patients with anaphylaxis history and 6 patients with negative skin test results who did not give consent were not challenged.
• Challenged with the culprit drugs, all the 13 patients with negative skin test results experienced HRs during the SBDPTs.
• Experts found skin test results with alternative drugs positive in only 2 patients with negative SBDPT results.
• With alternative macrolides, 5 patients with negative skin test results reacted to SBDPTs.
• In healthy control subjects, the skin test results were positive in 3 patients (1 positivity with clarithromycin, 2 positivity with spiramycin).
• On the other hand, all DPT results were negative.