Related Medical Conditions

Eczema, also called atopic dermatitis, is a common condition characterized by dry, itchy, inflamed skin. Eczema is primarily a problem with the skin itself and skin care is the main treatment. Some triggers may make eczema worse, such as certain types of weather (cold, dry in winter, or hot, humid in summer) and allergies. Food allergens do not commonly contribute to worsening of eczema in most patients with atopic dermatitis, especially those with mild disease.

Experts believe having eczema increases the risk a child may develop food allergies and other allergic conditions later in life. About one-third of children with moderate to severe eczema have diagnosed food allergies. Likewise, about 30 to 40 percent of all people with eczema also have one or more food allergies.

Often a person will experience and treat these conditions separately. When eczema is actually triggered by a food allergy, the reaction tends to be immediate. The foods most likely to causes eczema flares are milk and egg.

An allergist will rely on a combination of medical history and diagnostic tests to determine if you or your child has food-triggered eczema. It is common for patients with eczema to have false positive testing to foods so it is important to discuss such results with your allergist to make sure you are not removing a food unnecessarily. If you are diagnosed, your allergist will recommend that you avoid the problem food.

Infants and young children at risk for food allergy and eczema may benefit from early introduction of high-risk foods. Learn more about this research.

Asthma is a respiratory condition marked by inflammation in the lung’s airways. This leads to chest pain, wheezing, coughing and difficulty breathing. Symptoms may increase at night, following exercise or after exposure to an environmental allergen.

Rhinitis, also called hay fever, is an inflammation of the membranes that line the nose. Most commonly associated with allergies to pollen, dust, and/or furred animals, its symptoms include sneezing, runny nose and itchy eyes.

According to a recent study, young children with food allergies are more than twice as likely to develop asthma or rhinitis before age 5, compared to those without food allergies. The risk for respiratory allergies is higher in children who are allergic to milk, egg or peanut. This is also true for children with multiple food allergies. (See Atopic March, below.)

Chronic respiratory symptoms are not thought to be caused by food allergies. When respiratory symptoms occur during allergic reactions to foods, they occur suddenly and usually are not the only symptom. Instead, they appear alongside other symptoms affecting the skin, gastrointestinal tract and other parts of the body.

People with both asthma and food allergies are at higher risk of experiencing life-threatening anaphylaxis during a food allergy reaction. Research has similarly shown that having a food allergy is linked to having worse asthma symptoms and more hospitalizations from asthma.

Some people develop a series of allergic diseases called the Atopic March, or the Allergic March. This concept summarizes the typical sequence patients develop allergic diseases; starting first with eczema and, often, food allergy, followed by asthma and allergic rhinitis.

Researchers don’t yet know whether the Atopic March conditions merely coexist in people with overactive immune systems, or if there is an actual causal relationship among them.

This progression is most common in people who were diagnosed with eczema and food allergy in early childhood. However, the diseases don’t always develop in the same order, and not everyone will experience each one on the list.

Eosinophilic esophagitis (EoE) results when large numbers of eosinophils, a type of allergy-related white blood cell, gather in the esophagus (the tube that connects the mouth to the stomach). As a result, the lining of the esophagus becomes inflamed, making it difficult for food to go down. EoE is diagnosed by taking a biopsy from the esophagus and looking for eosinophils under a microscope. Certain foods can trigger EoE.

Symptoms vary, depending on age. With infants and toddlers, families often note feeding difficulties, irritability and poor weight gain. Older children typically have regurgitation (spitting up), vomiting, heartburn and belly pain. Teenagers and adults may have chest pain, difficulty swallowing and a feeling that food “gets stuck” when they swallow.

The best way to determine which foods are contributing to EoE is to remove the food from the diet and repeat the biopsy to see if the eosinophils have gone away. Allergy testing has not been shown to consistently indicate which foods are triggering symptoms.

Food protein-induced enterocolitis syndrome (FPIES) is a serious, non-IgE-mediated type of food allergy. FPIES is typically diagnosed in infancy and is often triggered by cow’s milk or soy. Other foods may also cause FPIES, especially the cereal grains rice or oat.

FPIES symptoms include severe, repetitive vomiting and sometimes diarrhea. Paleness, lethargy and limpness may also be noted. Reactions tend to happen two to six hours after eating the trigger food and may happen even if the food has been tolerated in the past a few times. The main treatment for an FPIES reaction is rehydration, and some patients are treated with intravenous fluids in the emergency room.

Medical professionals do not use standard food allergy tests for diagnosing FPIES. Often history alone is enough to make the diagnosis. If the diagnosis is not clear, an oral food challenge can be used to help. Often, FPIES resolves by school age.

Oral allergy syndrome (OAS), also known as pollen-food syndrome, refers to itchy or scratchy mouth symptoms caused by raw fruits or vegetables. It occurs in people who also have hay fever.

OAS happens when people who are allergic to pollen eat raw fruits or vegetables that have proteins similar to pollen proteins. This triggers an allergic response when the food is eaten. Because these proteins are sensitive to heating, most people affected by OAS can eat cooked fruits or vegetables. 

Symptoms are usually limited to the mouth. They usually go away minutes after the food is swallowed or removed from the mouth. Treatment generally is not necessary. However, a minority of people with OAS have symptoms that extend beyond the mouth, and some even experience anaphylaxis.

OAS typically presents in older children, teens or young adults. Its onset can be sudden, often after patients have been eating the offending foods without problems for many years.

Lactose intolerance occurs when a person’s small intestine does not produce enough of the lactase enzyme. As a result, affected individuals are not able to digest lactose, a type of sugar found in dairy products.

The symptoms typically occur within 30 minutes to two hours after ingesting dairy products. Large doses of dairy may cause increased symptoms.

Many people confuse lactose intolerance with milk allergy. Learn more about the differences.

Celiac disease, or celiac sprue, is an adverse reaction to the protein gluten. Gluten is found in wheat, rye, barley and sometimes oats, which may come into contact with grains that contact gluten. People with celiac disease must strictly avoid these grains and their byproducts for the rest of their lives.

When people with this digestive disease eat gluten, they experience an immune reaction in the small intestine. IgE, the antibody responsible for life-threatening reactions (anaphylaxis), does not play a role in this disorder. However, the immune response in celiac disease may damage the lining of the small intestine. This prevents the body from properly absorbing the nutrients in food. Over time, patients may become malnourished.

Celiac disease symptoms include bloating and gas, diarrhea, constipation, headaches, itchy skin rash and pale mouth sores. The symptoms may vary among affected individuals.