Tag: cross-reactivity

by Malcolm Hitchcock
Feb 11, 2026
0 Comments

Antihistamine Allergies and Cross-Reactivity: What to Watch For

Some people develop hives or swelling from antihistamines meant to treat allergies. This rare paradoxical reaction can occur with any common drug - even if skin tests are negative. Learn what causes it, how to spot it, and what to do next.

by Malcolm Hitchcock
Jan 16, 2026
15 Comments

Sulfonamide Allergies and Cross-Reactivity: What Drugs to Avoid and What’s Safe

Most people labeled with sulfa allergy aren't truly allergic. Learn which sulfonamide drugs you can safely take, which ones to avoid, and how to fix a misdiagnosed allergy to get better, safer treatment.