How Long Would An Allergic Reaction Last (And Why)?

How Long Would An Allergic Reaction Last (And Why)?

Exact Answer: 5 Minutes To 1 Month

Allergic reactions are quite common, though some are more common than others. An allergy is the reaction of the body’s immune system to harmful substances. People with certain allergies are very sensitive as any little negligence can be very harmful.

People are allergic to different things, and it solely depends from person to person. It is believed that developing allergies could be hereditary, but it doesn’t mean that everyone in the family gets them. When the body tends to have an allergic reaction, people experience cough, rashes, fever, and other such reactions.

How Long Would An Allergic Reaction Last

How Long Would An Allergic Reaction Last?

The lasting time of an allergic reaction differs from one to another. It is considered that most allergic reactions are mild, but there are some which need urgent treatment. Different allergic reactions have different symptoms, and though more or less the period is the same for them to last.

The exact time cannot be assumed as everybody’s body works differently. Mentioned below are some of the most common types of allergies that people experience:

Food: A food allergy takes place when a person’s body reacts to a particular food. It could be dry fruits, milk & milk products, or maybe any fruit or vegetable. While the time for a food allergy to last depends on the intensity of the allergic reaction, the amount of food you eat, and its type.

Seasonal: As the name suggests, seasonal allergies occur when there is a change in the climate. The most common symptoms are runny nose, hay fever, but these allergic reactions are manageable to a great extent. Such reactions go away in a few days with the changes in the environment.

Skin: Many people experience skin allergies due to direct exposure to an allergen. It includes rashes, sore throat, itching, and burning. Such allergies don’t go away on their own and need treatment. It takes more time, even months, to go away compared to other allergic reactions.

Severe: Severe allergic reactions (irrespective of their source) are mostly fatal and need urgent treatment. The most common severe type of allergic reaction is known as anaphylaxis. The body’s response is very sudden and it could reach the peak even in 5-30 minutes.

Allergic Reaction


Type of AllergyTime
Food5 Minutes to 18 Hours
Seasonal18 Hours to 7 Days
Skin1 Week to 1 Month
Severe5-30 Minutes

Why Does An Allergic Reaction Last So Long?

There are a lot of factors that influence the duration of an allergic reaction. The allergic reaction may seem to be getting better with time. Allergic reactions do take time to go away because the body heals itself slowly and gradually. Though some may not last for more than a few hours, others could last for a reasonably long duration.

Most of these reactions are reversible but do require some sort of precautions and treatments. Like it could be a good option to take a medicated bath for body reactions like rashness and itching, as it could give relief. Sometimes a reaction can be minor and the symptoms seem like a one-time reaction, that is, face itches for a while after eating it. Similarly, reactions from certain foods could require medical treatment.

Allergic Reaction

People with food allergies must always avoid even a small quantity of that food. It can take a long time for the body to completely remove protein from foods, so it is advisable to take antihistamines available at home. In the case of seasonal allergies, a variety of treatments are available. What works best depends on your allergen-inducing immune system and other personal factors. One way is to leave an area where allergies are prevalent.


The more severe and repeated exposure to an allergen, and the earlier it occurs in life, the more likely you are to develop an allergy. There are varying periods for allergic reactions to go away. Everyone’s body reacts differently in different situations.

Similarly, depending upon the type of allergy and a person’s immune system the reaction can be mild to severe. There is no hard and fast rule for how a reaction may occur, so it is advisable to act according to the situation, and in severe cases, a doctor must not be avoided.


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24 thoughts on “How Long Would An Allergic Reaction Last (And Why)?”

  1. A very well researched and written article and the information is presented in an organized and structured manner. I am impressed!

  2. This is an informative article on different types of allergies and the time their reactions last, it’s very useful.

  3. Avatar of Matthews Leanne
    Matthews Leanne

    The article nicely explains the different types of allergies and the duration of their reaction, great content.

  4. This was a good read, but the part about why allergic reactions last for so long could have been better explored.

  5. I never knew the difference between the different types of allergies and the duration of their reaction, this is very interesting.

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