Systemic reaction during intradermal skin tests with beta-lactams.

Area of Science:

• Allergy and Immunology
• Pediatric Allergy
• Pharmacovigilance

Background:

• Beta-lactam (BL) antibiotics are the most common cause of drug hypersensitivity in children, manifesting as immediate or non-immediate reactions.
• Non-immediate reactions, often appearing days after drug exposure, pose diagnostic challenges.

Observation:

• A 4-year-old child presented with a disseminated maculopapular exanthema 7 days post-amoxicillin-clavulanate.
• Initial skin prick tests were negative.
• Intradermal testing with amoxicillin and amoxicillin-clavulanate resulted in delayed systemic reactions, including indurated wheals and widespread rash after 10 hours.

Findings:

• This case highlights a rare non-immediate systemic reaction to intradermal BL testing.
• The reaction occurred significantly later than typically observed immediate responses to skin tests.
• The findings link amoxicillin and amoxicillin-clavulanate to the observed delayed hypersensitivity.

Implications:

• Emphasizes the importance of considering delayed reactions in BL hypersensitivity.
• Suggests intradermal skin testing may be valuable for diagnosing non-immediate reactions to BL antibiotics.
• Underscores the need for careful skin testing prior to drug provocation tests in pediatric allergy evaluations.