How long does an allergic reaction to food last

Food allergies occur when your body overreacts to the proteins in specific foods. This overreaction is called an allergic reaction.

What are the types of food allergies?

You can have an allergy to any type of food. Eight types of food account for about 90% of all food allergies. These foods are:

• Eggs.
• Fish.
• Milk.
• Peanuts.
• Shellfish.
• Soy.
• Tree nuts.
• Wheat.

How common are food allergies?

Food allergies affect more than 50 million Americans. About 4% of adults have food allergies. Food allergies affect up to 6% of children.

How do food allergies affect my body?

Your immune system identifies and destroys harmful bacteria and viruses. When you have a food allergy, your immune system mistakenly identifies a food protein as something harmful. Coming in contact with that protein triggers an allergic reaction.

Are food allergies the same as food intolerances?

Food allergies are not the same as food intolerances. Allergies cause a response in your immune system. Allergies can be life-threatening.

Food intolerances cause a response in your digestive system. You may be able to eat a small amount of a food you are intolerant to without experiencing symptoms. Intolerances can be uncomfortable but aren’t usually dangerous.

Food allergies tend to run in families. If you have other allergic conditions, such as hay fever or eczema, you may be more likely to have a food allergy. You are also more likely to experience food allergies if you have asthma.

What are the symptoms of food allergies?

Usually, you experience food allergy symptoms within two hours of eating. The symptoms of food allergies can range from mild to severe. If you have an allergic reaction, you may experience:

Are there any life-threatening symptoms of food allergies?

The most severe allergic reaction to a food is anaphylaxis. Anaphylaxis is a rapidly progressive reaction that sends your body into shock. It can make it hard or impossible to breathe. Without medical treatment, anaphylaxis can be life-threatening.

Food allergies cause similar reactions each time you eat a trigger food. To make a diagnosis, a healthcare provider may ask you:

• How long it takes for your symptoms to develop.
• What and how much of a certain trigger food you ate.
• What symptoms you experience and for how long.

What tests are used to diagnose food allergies?

If you suspect you have a food allergy, allergy/immunology providers can perform a skin test to confirm it. During a skin test, your healthcare provider:

1. Applies a small amount of different types of allergens (allergy-causing substances) to your skin on your arms or back.
2. Makes tiny pricks or scratches through the allergens.
3. Measures your reactions to the allergens after tests have been in place for 15 minutes.

Areas of your skin that become red and itchy indicate an allergy. Your healthcare provider uses this information to determine what you’re allergic to.

Your healthcare provider may also use a radioallergosorbent blood test (RAST). A RAST checks the levels of allergic antibody to different allergens in your blood. Raised levels of specific antibodies can indicate an allergy.

When you know what foods you are allergic to, the best approach is to strictly eliminate those foods from your diet and to have emergency medications including epinephrine autoinjectors available at all times in case of accidental ingestion and reaction. It’s important to seek emergency medical care immediately after using an epinephrine autoinjector. Wearing a medical alert identification indicating your food allergies is also recommended.

Your healthcare provider may prescribe medicines that reduce your allergic reaction symptoms. These medicines include:

• Epinephrine (for example, EpiPen® or Auvi-Q), a lifesaving emergency medication that immediately begins reversing symptoms of anaphylaxis.
• Antihistamines, medications that reduce itching or congestion.
• Corticosteroids to reduce swelling if you have a severe allergic reaction.

How can I avoid food allergy triggers?

To avoid the foods you are allergic to, you must carefully check the ingredient labels on food products. Food manufacturers must clearly state on the label if a product contains any of the eight most common food allergens.

Some labels use precautions such as “may contain” or “made on shared equipment.” If you have any questions about what you can and can’t eat, ask your healthcare provider.

There is no known way to prevent food allergies in adults. In babies, breastfeeding in the first six months of life may prevent milk allergy. Early introduction of highly allergenic foods such as peanut protein and eggs into the diet may also have a preventative effect. Please discuss with your healthcare provider.

You can live a healthy life with a food allergy. If you have a food allergy, you need to carefully avoid all foods and ingredients that cause allergic reactions.

You may also need to take a nutritional supplement to replace any nutrients lost by avoiding your trigger foods. Speak with your healthcare provider or dietitian before starting a new eating plan.

If eating specific foods causes uncomfortable symptoms, see a healthcare provider for diagnosis and treatment.

When should I go to the ER?

Without medical treatment, allergic reactions can be life-threatening. Go to the ER or call 911 if you experience:

• Difficulty breathing.
• Chest tightness.
• Hives all over your body.
• Tingling hands, feet or lips.
• Throat swelling that constricts your airway.

A note from Cleveland Clinic

Food allergies occur when your body mistakenly triggers an immune response to certain foods. This immune response, or allergic reaction, can cause a variety of symptoms such as hives, swelling or difficulty breathing. In severe cases, you may experience a life-threatening reaction called anaphylaxis. Once you know what foods you are allergic to, the best way to manage your allergy is to avoid those specific foods. Healthcare providers can prescribe medications that reverse anaphylaxis and other allergy symptoms.

Last reviewed by a Cleveland Clinic medical professional on 03/24/2021.

References

• American Academy of Allergy Asthma & Immunology. Food Allergy Overview. (https://www.aaaai.org/Conditions-Treatments/Allergies/Food-Allergy) Accessed 4/7/2021.
• U.S. Food and Drug Administration. Food Allergies. (https://www.fda.gov/food/food-labeling-nutrition/food-allergies) Accessed 4/7/2021.
• American College of Allergy, Asthma & Immunology. Food Allergy. (https://acaai.org/allergies/types/food-allergy) Accessed 4/7/2021.
• Food Allergy Research & Education. What Is a Food Allergy? (https://www.foodallergy.org/resources/what-food-allergy) Accessed 4/7/2021.

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Food allergies

More than 50 million Americans have an allergy of some kind. Food Allergy Research and Education (FARE) estimates up to 15 million people in the United States have a food allergy.

A rash is one of several common symptoms that can occur if you have an allergic reaction to a food. Keep reading to learn more about what food rashes may look like and what you can do about them.

Signs of a food allergy rash

Food allergy reactions don’t always include rashes. However, rashes associated with food allergies have symptoms such as:

• hives
• redness
• itchiness
• swelling

A rash tends to develop shortly after coming into contact with the food. With a food sensitivity it may appear around your mouth, neck, or face — basically anywhere food has come into contact with your skin.

It’s also possible to have a rash on other parts of your body. This is more common with a food allergy. Overall, the symptoms of a food allergy rash are the same among children and adults.

You may be able to tell your rash is from a food allergy if you also have other symptoms of a food allergy, such as:

• abdominal cramps
• diarrhea
• itchy or watery eyes
• itchy, stuffy nose
• sneezing
• vomiting

Food allergy rash pictures

Food allergy rash causes

Food allergy rashes are caused by ingesting foods you’re allergic to. Your immune system treats the proteins in the food as harmful substances and tries to fight them. Even trace amounts can lead to an allergic reaction.

According to the American Academy of Allergy, Asthma, and Immunology (AAAAI), the most common food allergens include:

• cow’s milk
• eggs
• fish
• nuts
• peanuts
• shellfish
• soy
• wheat

While these are the most common, it’s possible to be allergic to any food. In fact, FARE estimates that at least 170 foods can cause allergies.

There’s also the possibility of cross-reactivity. For example, if you’re allergic to ragweed, you could also be allergic to foods in the same family, such as melons. A common cross-reactive allergy is latex and foods. People with latex allergies may also be allergic to fruits including bananas, kiwi, and avocado.

Food allergies are often detected during early childhood as a result of an adverse reaction to a particular food. Blood or skin tests can also help diagnose food allergies. Many children outgrow food allergies, but it’s possible to have lifelong allergies. Adults can also develop new food allergies, though this is less common.

The only way to avoid an allergic reaction is to avoid a food allergen entirely. While food labels are very important, it’s also important for you to be prepared in case of a reaction.

Food allergy rash treatment

Food allergy rashes eventually subside once the underlying reaction stops. One of the best ways to help is to stop your exposure to the allergen.

Wash up

Wash your hands and face, if needed, as well as any surfaces that may have come in contact with the suspected food. This can help prevent more rashes. Some people rinse off with a quick shower.

Apply a soothing cream or gel

If the rash is bothersome, you can apply over-the-counter (OTC) creams, such as hydrocortisone.

Take an antihistamine

An oral antihistamine can also help. These will help alleviate the itchiness, inflammation, and overall discomfort.

There are different OTC antihistamines, each with a different active ingredient. Some may work better than others for you and your symptoms. It takes time for the antihistamine to build up in your system. You shouldn’t mix antihistamines. Take one type of antihistamine as directed while your rash is present.

Read more about different antihistamine brands such as Benadryl, Claritin, and Allegra.

Speak to a doctor

For your long-term health and comfort, it can be helpful to consult an allergist or even a nutritionist or dietitian. An allergist can help you to identify your allergens and determine what OTC antihistamine is appropriate for you.

In addition, a nutritionist or dietitian can provide you with useful tips and suggestions for foods so you avoid your allergy trigger while still getting the right nutrition.

How long does a food allergy rash last?

A food allergy rash may not appear until your immune system reacts to the food. Depending on the food and the amount you ingest, this can take a few hours. Other cases can develop within minutes.

Scratching at it can make it last longer. This can also increase your risk for skin infection.

Once your immune system calms down, your symptoms will subside. Antihistamines and topical creams can help alleviate minor symptoms. Overall, the rash should subside within a day or two.

According to FARE, it’s possible to have a second wave of food allergy symptoms, which may occur up to four hours after the initial reaction, though this is rare.

Call your doctor if you think your initial food allergy rash has become infected. Signs may include inflammation, pain, and discharge. The size of the rash can also increase if it’s infected.

Food allergy rash and anaphylaxis

The most severe type of allergic reaction is anaphylaxis, which is a life-threatening condition. This is not a complication of a food rash itself, but rather a complication of the overall allergic reaction. Hives and anaphylactic reactions often occur together, but you can have hives without having anaphylaxis.

On top of the food allergy symptoms listed above, anaphylaxis may cause:

• breathing difficulties
• chest pain
• dizziness
• fainting
• low blood pressure
• severe swelling in the mouth, face, neck, and throat
• tightness in the throat
• tingling lips, hands, and feet
• wheezing

If your doctor recommends epinephrine shots for severe food allergies, it’s important to keep them on hand at all times. Even breathing in a food allergen can cause severe issues. Also, the severity of a reaction may vary — just because one reaction was mild, doesn’t mean the next will also be mild.

Anaphylaxis is a medical emergency. Call 911 or your local emergency services and take your epinephrine shot as soon as you experience symptoms. Antihistamines can’t treat anaphylaxis because the symptoms are too severe at this stage.

Food allergy rash vs. food intolerance

A food allergy occurs when your immune system adversely reacts to proteins in a certain food you’re allergic to. This is not the same thing as a food intolerance.

Food intolerance is primarily a digestive issue that can cause symptoms similar to food allergies, except that it’s not life-threatening.

Non-itchy rashes from a food intolerance can also develop over time, such as “chicken skin” on arms. This is unlike a food allergy rash, which tends to occur within minutes or hours of eating the suspected food. Food intolerance can also cause bloating, stomach pain, and mild digestive upset.

Another key difference is that you can sometimes have small amounts of a food without a problem if you have an intolerance. With an allergy, even a small amount of the food can cause issues.

According to the AAAAI, most suspected cases of food allergies are actually intolerances. However, you don’t want to take a chance with self-diagnosis. An allergist can help you determine the difference.

The takeaway

If you suspect moderate to severe food allergies, make an appointment with an allergist. This type of specialist can accurately diagnose food allergies and rule out any possible food sensitivities.

Since there’s no cure for food allergies, the best way to prevent them — and subsequent symptoms like rashes — is to avoid the culprit completely.