A life-threatening allergic reaction (anaphylaxis) can cause shock, a sudden drop in blood pressure and trouble breathing. In people who have an allergy, anaphylaxis can occur minutes after exposure to a specific allergy-causing substance (allergen). In some cases, there may be a delayed reaction, or anaphylaxis may occur without an obvious trigger. Show
If you're with someone having an allergic reaction with signs of anaphylaxis:
If you're with someone having symptoms of anaphylaxis, don't wait to see whether symptoms get better. Seek emergency treatment right away. In severe cases, untreated anaphylaxis can lead to death within half an hour. An antihistamine pill, such as diphenhydramine (Benadryl), isn't enough to treat anaphylaxis. These medications can help relieve allergy symptoms, but they work too slowly in a severe reaction. Symptoms of anaphylaxis include:
Some common anaphylaxis triggers include:
If you've had any kind of severe allergic reaction in the past, ask your doctor if you should be prescribed an epinephrine autoinjector to carry with you. Sign up for
free, and stay up to date on research advancements, health tips and current health topics, like COVID-19, plus expertise on managing health. To provide you with the most relevant and helpful information, and understand which information is beneficial, we may combine your email and website usage information with other information we have about you. If you are a Mayo Clinic patient, this could include protected health information. If we combine this information with your protected health information, we will treat all of that information as protected health information and will only use or disclose that information as set forth in our notice of privacy practices. You may opt-out of email communications at any time by clicking on the unsubscribe link in the e-mail. July 02, 2022
See also
. How much Benadryl can i take at once for allergic reaction?Use Adult BENADRYL® products. 1 to 2 tablets every 4 to 6 hours. Do not exceed 8 tablets in 24 hours. Apply to affected area not more than 3 to 4 times daily.
Can I take 2 Benadryl for allergic reaction?Do not take more than 6 doses in 24 hours. Use only as directed. Take 1 to 2 tablets every 4 to 6 hours or as directed by a doctor. Take 1 tablet every 4 to 6 hours or as directed by a doctor.
How long does it take for Benadryl to work for allergic reaction?It normally takes about 30 minutes to work. Common side effects include feeling sleepy, dizzy or unsteady on your feet. You may also have difficulty concentrating and have a dry mouth.
Will Benadryl clear up an allergic reaction?An antihistamine pill, such as diphenhydramine (Benadryl), isn't enough to treat anaphylaxis. These medications can help relieve allergy symptoms, but they work too slowly in a severe reaction.
|