Are you or your child experiencing persistent itching lately? Dealing with skin reactions can be uncomfortable and alarming, and naturally, you want to take steps to prevent them. How can you tell if these symptoms are caused by a skin condition like eczema or if they are the result of food allergies?

Eczema is a skin condition characterized by dryness and itchiness. The most common type is atopic dermatitis. Eczema can be related to food, the environment, and even internal factors like stress. Food allergies, on the other hand, occur when your body incorrectly perceives certain foods as threats. This can lead to many symptoms — including itchy rashes.

Children with eczema often have food allergies as well: Approximately 30 percent of children 5 and younger with eczema also have food allergies. Moreover, eczema is considered a major risk factor for the development of food allergies.

Food allergies and eczema share a lot of common features but ultimately have different causes and courses of treatment. By gaining a deeper understanding, you can better find ways to relieve discomfort for yourself or your child. If you or a loved one is experiencing any of these symptoms, it is best to talk to your doctor.

Here are three ways that food allergies and eczema are similar.

1. Both Food Allergies and Eczema Are Related to the Immune System

Both food allergies and eczema involve an exaggerated response from the immune system. In the case of food allergies, the immune system reacts to specific foods, perceiving them as threats. This triggers the production of immunoglobulin E (IgE) antibodies, which attach to proteins in the food, enabling immune cells to release inflammatory chemicals. Among these chemicals are histamines, which play a significant role in causing the symptoms of an allergic reaction, such as itching, swelling, and digestive issues.

With eczema, the immune system similarly overreacts to irritants or allergens, resulting in inflammation of the skin. Immune cells are also involved in this process, but they release different types of inflammatory chemicals, not always histamines. Although the precise chemicals released during an eczema flare-up are not yet fully understood, they are responsible for the swelling, itching, and skin discoloration associated with eczema.

2. Eczema and Food Allergies Can Both Cause Itchy Skin

Both food allergies and eczema can result in skin reactions. For both conditions, a rash is a common outcome. In food allergies, ingesting an allergenic food — a food your body considers to be harmful — triggers an allergic reaction. Allergic reactions can be related to the skin or show up in other ways. These include:

• Hives — Bumps on the skin
• Itching — Itchy skin, especially on areas with hives
• Swelling — Swollen skin and swelling of the mouth, tongue, and throat
• Difficulty breathing — Respiratory trouble related to the swelling of the mouth and throat
• Digestive issues — Vomiting, nausea, abdominal cramps, and diarrhea

Swelling of the mouth, tongue, and throat, in addition to breathing trouble, digestive problems, and cardiovascular changes, can be symptoms of a life-threatening allergic reaction called anaphylaxis. These signs require immediate treatment with epinephrine, such as an Auvi-Q or EpiPen auto-injector, and contacting 911 or emergency services right after using the auto-injector.

Unlike a food allergic reaction, eczema’s symptoms are usually restricted to the skin. Eczema can cause itchy and inflamed patches of skin, often accompanied by oozing, crusting, or thickening. Eczema is also occasionally associated with hives.

3. Food Allergies and Eczema Share Some Common Triggers

There can be overlapping triggers between food allergies and eczema. For some individuals with eczema, certain foods can worsen their symptoms. Likewise, some individuals with food allergies have eczema as a reaction. Common food triggers for both eczema flares and food allergies include:

• Cow’s milk
• Eggs
• Nuts and sesame seeds
• Soy
• Wheat
• Fish and shellfish

Unlike food allergies, eczema flare-ups can also be triggered by environmental factors that disrupt the skin barrier. These include:

• Topical irritants, like scented detergents or lotions
• Climate, such as cold and dry weather
• Environmental allergens, like pollen and dust mites
• Stress
• Illness

While food allergies and eczema are both reactions of the immune system that can cause itchy skin, they also have important differences. A doctor will likely use different tests to diagnose food allergies and eczema. They will recommend different treatment methods, depending on how each condition shows up in the body.

Here are three important differences between eczema and food allergies.

1. Food Allergies and Eczema Affect Different Organs in the Body

Food allergies and eczema tend to affect different organ systems. Food allergies can affect multiple organ systems, such as:

• The digestive system — Food allergies can cause severe abdominal pain, nausea, and vomiting.
• The respiratory system — Food allergies can cause severe swelling of the throat, tongue, and airways, making it hard to breathe.
• The cardiovascular system — Histamines from an allergic reaction can cause blood vessels to expand and decrease blood pressure.
• Skin — Food allergies can lead to hives, rashes, and itchy skin.

Eczema, on the other hand, primarily affects the outermost layer of the skin, causing inflammation and itchiness. While eczema can be a symptom of a food allergy, it isn’t always one.

2. Doctors Use Different Methods To Diagnose Food Allergies and Eczema

The diagnosis of food allergies is different from that of eczema. While both diagnoses involve a medical examination by your doctor and a review of your medical history, food allergies require more advanced testing by a specialist called an allergist.

These tests include:

• Skin prick test — A doctor will prick your skin and apply a small amount of a food allergen. If your skin reacts with swelling or inflammation, this can indicate you are allergic to this allergen.
• Allergy blood test — Your blood will be tested for the presence of IgE antibodies specific to certain food allergens.
• Oral food challenges — Eating potential food allergens under medical supervision is the best way to test for an allergy. However, it can be time-consuming, and there are health risks associated with it.

Eczema is typically diagnosed based on a physical examination and a review of your medical history. You may seek out a skin doctor, called a dermatologist, or an allergist. Diagnostic tests are not usually necessary for eczema, unless your doctor suspects an underlying allergy or infection.

3. Treatments for Food Allergies and Eczema Are Not the Same

Treating food allergies and eczema requires different strategies. Because food allergies involve a specific edible allergen that is responsible for causing inflammation, treatment usually revolves around strictly avoiding that food.

With food allergies, treatment may look like:

• Strictly avoiding the food allergen, even when it is used in the preparation of other foods
• Having emergency medication on hand, such as oral antihistamines or two Auvi-Q or EpiPen auto-injectors containing epinephrine
• Taking oral immunotherapy, small and incremental doses of the food allergen, daily under the supervision of an allergist. Although not a cure, this can increase the amount of the food allergen a person is able to eat before experiencing symptoms.

Research suggests that epicutaneous immunotherapies, in which patches with a small amount of food allergen are worn on the skin, could be effective for treating individuals with food allergies. These treatments are still under investigation.

Emergency medications treat allergic reactions to a food allergy. They are not used to cure the allergy. They are also not usually effective in treating eczema, although antihistamines are often still recommended for eczematic itching.

Eczema treatment focuses primarily on managing symptoms, reducing inflammation, and restoring the skin barrier. This may involve using topical creams to keep the area moist and topical medications, such as steroid creams, for reducing inflammation. Avoiding triggers that can cause an eczema flare and taking soothing lukewarm baths can help eczema flare-ups. There are also medications that modify the immune system, which your doctor may prescribe.

Food allergies and eczema are both caused by immune system reactions and can be triggered by similar allergens. But diagnosing and treating them requires different methods and the supervision of a doctor. If you have noticed the symptoms mentioned in this article, share them with your health care provider.

Talk With Others Who Understand

MyFoodAllergyTeam is a social network for people with food allergies and their loved ones. On MyFoodAllergyTeam, more than 39,000 members come together to ask questions, give advice, and share their stories with others who understand life with food allergies.

Have you experienced eczema or a rash as a symptom of your food allergy? How did you discover the cause, and what helped you feel better? Share your experience in the comments below, or start a conversation by posting on your Activities page.