Overview

Allergies to citrus fruits are rare, but they do occur. Citrus fruits include:

  • oranges
  • lemons
  • limes
  • grapefruits

You may have an allergic reaction to the fresh fruit and juice of citrus fruits or to the peels. Keep reading to learn more about what causes a citrus allergy and citrus allergy symptoms.

Citrus allergy symptoms

Most people who have a citrus allergy experience symptoms after eating food or a drink made with raw citrus fruit. The symptoms are often localized, which means that you feel them wherever the raw fruit touched your skin. Symptoms include:

  • intense tingling and itching of the lips, tongue, and throat
  • reddening and mild swelling of the lips and gums

These are the symptoms of oral allergy syndrome (OAS). Individuals with OAS who have reactions to citrus fruits can usually eat the fruits when they’re cooked. Symptoms may appear later in life, even if you’ve been eating the fruit for years with no problems.

People who are allergic to citrus fruit peels may experience symptoms of contact dermatitis if they come in contact with the peel of citrus fruit. Allergic contact dermatitis is caused by your skin releasing inflammatory chemicals after coming into contact with an allergen. Symptoms include:

  • skin redness
  • skin that burns
  • extreme itching
  • dry, scaly, flaky skin
  • swelling
  • blisters

In rare cases, a citrus allergy can cause a systemic allergic reaction, also called anaphylaxis. Anaphylaxis is a medical emergency and can be life-threatening. Symptoms of anaphylaxis include:

  • hives
  • flushed skin
  • swelling of the mouth and throat, which can make breathing difficult
  • asthma
  • nausea, vomiting, or diarrhea
  • drop in blood pressure, causing you to feel weak

Seek emergency medical help if you are experiencing any of the symptoms of anaphylaxis.

First aid you should know: How to treat allergic reactions »

Citrus allergy causes

An allergic reaction is due to your immune system mistakenly defending your body against substances that typically don’t pose a threat to you. These substances are known as allergens. When your immune system reacts to an allergen, it causes an allergic reaction.

Allergic reactions to raw citrus fruits are sometimes seen in people who have pollen allergies, in a phenomenon known as cross-reactivity. Other people may experience an allergic reaction after coming in contact with the peels of citrus fruits. There are also documented cases of some citrus fruits causing a severe allergic reaction known as anaphylaxis, although this is very rare.

One thing that can’t cause an allergic reaction is citric acid. Citric acid is a chemical found in the juice of citrus fruits, giving them their tart flavor. Citric acid itself is not an allergen, although it can cause skin and mouth irritation, and even an upset stomach. However, citric acid doesn’t trigger an immune system response, so while you may be sensitive to it, it isn’t technically an allergen.

Cross-reactivity

Many allergic reactions to citrus are due to OAS, which is caused by pollen allergies. This is known as cross-reactivity, which occurs because pollen and citrus fruits share certain proteins. These shared proteins cause the body to react to a mouthful of fruit as if the bite delivered the allergy-causing pollen instead. This pollen-food cross-reactive allergy causes OAS.

People who are allergic to grasses in particular may experience OAS to citrus fruits. A 2013 study took a look at 72 children and young adults with grass pollen allergies. They exposed participants to the fruit of fresh lemon, orange, and clementine with a prick test, and found that 39 percent of the participants who were allergic to pollen also had sensitivities to citrus.

Limonene allergy

People who are allergic to citrus fruit peels are often allergic to limonene, a chemical found in the peels of citrus fruits. Just touching the outside of a citrus fruit can cause contact dermatitis symptoms for these people, but they may be able to drink fresh juice just fine. Limonene is also often used as a fragrance in cosmetics and perfumes.

Systemic allergy

There isn’t much information available about how many people experience a systemic allergy to citrus fruits, but there are documented cases of people having a severe, anaphylactic reaction to oranges and other citrus fruits. There have also been cases of food-dependent exercise-induced anaphylaxis with oranges and grapefruits. This is a specific form of food allergy in which an allergic reaction occurs only after ingesting the allergen and then exercising soon after.

More research needs to be done to discover how many people have systemic allergies to citrus fruits.

Diagnosing citrus allergies

If you or your child shows a reaction to pollen, your doctor will do a skin-prick test and talk to you about possible fruit allergies. A skin prick test involves a simple prick with a needle that inserts a small amount of the suspected allergen. If you’re allergic, you’ll develop a bump with a red ring around it in 15 to 20 minutes.

If your child is too young to tell you if they are bothered by some fruit, keep a close eye when trying new things and monitor any reactions.

Call for medical help right away if you suspect anaphylaxis. If your allergy is severe your doctor will recommend that you carry an EpiPen with you.

Foods to avoid

If you think you or someone in your family is allergic or sensitive to citrus, the elimination diet is the best way to keep safe. Avoid the following citrus-containing foods:

Foods to avoid

  • Avoid anything from raw citrus fruit to citrus fruit juice. Check the label when buying other types of juices as well, as sometimes citrus juice will be mixed in for some extra punch.
  • Avoid unripe or freshly picked citrus. Unripened citrus can be an irritant, more so than ripened fruit.
  • Avoid citrus fruit seeds and rinds. People often add citrus zest rind to their baking and salads. Always ask about the ingredients when eating out or at someone else’s home.
  • Avoid artificially-flavored sweets and vitamin C supplements, as they often use citrus flavoring.

Through citrus fruit can cause reactions when eaten raw, many people can safely consume them cooked. Cooking deactivates the allergic proteins in many cases. You can also try herbs like lemon verbena and sumac as substitutes for the tart citrus flavor, if a recipe calls for citrus fruit or zest.

Q&A: Citrus allergy in babies

Q:

My baby has some reactions to citrus fruits. Could he or she be allergic?

A:

It depends on the reaction your baby is having to citrus fruits. It is possible that he or she is having an allergic reaction. Monitor your baby closely to look for signs of a rash or more seriously signs of anaphylaxis which will require immediate hospitalization. If you suspect your baby is having an allergic reaction, then stop any exposure to citrus fruit. Tell your doctor about your baby’s reaction so your doctor can determine if your baby needs allergy testing.

Alana Biggers, MDAnswers represent the opinions of our medical experts. All content is strictly informational and should not be considered medical advice.