1 doctor weighed in:

How long does it take for an allergic reaction appear?

1 doctor weighed in
Dr. David Shulan
Internal Medicine - Allergy & Immunology

In brief: Depends

Immedite type reactions can occur i minutes.
Contact allergies can take several days to show itself. Some drugs reactions can appears as long as 2 weeks after stopping the antibiotic and can persist for up to 6 months. Some sensitivities will not show at the first exposure, will show only with subsequent exposures.

In brief: Depends

Immedite type reactions can occur i minutes.
Contact allergies can take several days to show itself. Some drugs reactions can appears as long as 2 weeks after stopping the antibiotic and can persist for up to 6 months. Some sensitivities will not show at the first exposure, will show only with subsequent exposures.
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