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How Long Will A Drug Allergic Reaction Last. Sulfonamide drug hypersensitivity syndrome. Your immune system may become sensitive to the antibiotic the first time you take it. The reaction can also cause these serious skin reactions. They may take a few hours to a few days to disappear.
Privacy Trust Info Allergic reactions may last for varying lengths of time. Red or swollen rounded patches form in 30 minutes to 8 hours. Some people may react right away while others might take the drug several times before they have an allergic reaction. The symptoms of drug allergy may happen immediately or after taking the drug for a week or more. You may have an allergic reaction the next time. People with severe reactions may take a long time to get better especially if they are elderly or have other medical conditions.
You may have an allergic reaction the next time.
Most people with drug allergy recover very quickly once the medication is stopped although the rash can take 10-14 days to fade. It usually takes more time even months to go away compared to other allergic reactions. Sulfonamide drug hypersensitivity syndrome. If the exposure to the allergen continues such as during a spring pollen season allergic reactions may last for longer periods such as a few weeks to months. Some people may react right away while others might take the drug several times before they have an allergic reaction. Symptoms of a drug allergy may start right after you take it.