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Flare up to betalactams.
I Reig Rincón de Arellano1, A L Villalón García, M Cimarra Alvarez-Lovell
1Allergy Service. Hospital Clínico San Carlos. Madrid. Spain. irrda@hotmail.com
Allergologia Et Immunopathologia
|November 17, 2005
Summary
Delayed allergic reactions, known as flare-ups, can occur with antibiotics like amoxicillin and penicillin. This case suggests a T-cell mediated mechanism, not IgE antibodies, is responsible for these delayed drug hypersensitivity reactions.
Area of Science:
- Immunology
- Pharmacology
- Dermatology
Background:
- The flare-up phenomenon is commonly associated with nickel allergies.
- Drug-induced flare-ups are rarely reported in medical literature.
- This study investigates a case of delayed allergic reaction to antibiotics.
Observation:
- A 31-year-old woman experienced a delayed adverse reaction to amoxicillin.
- Initial allergy tests (prick, intradermal) for penicillin and related antibiotics were negative.
- An oral challenge with amoxicillin triggered positive intradermal tests and a widespread skin reaction (exanthema, pruritus).
Findings:
- Delayed positive intradermal tests to penicilloyl polylysine (PPL) and minor determinant mixture (MDM) occurred 12 hours post-challenge.
- Patch tests were positive after 72 hours, showing erythema, vesicles, and infiltration.
- The patient exhibited a generalized exanthema with pruritus, indicative of a systemic allergic response.
Implications:
- This case highlights a delayed allergic reaction to amoxicillin and penicillin, termed 'flare-up'.
- The reaction appears mediated by a Type IV (T-cell mediated) hypersensitivity mechanism, distinct from typical IgE-mediated beta-lactam allergies.
- Understanding these alternative mechanisms is crucial for diagnosing and managing delayed drug hypersensitivity.