Although food allergy is more common in young children, there are about nine million adults (4%) in the U.S. who suffer from one or more food allergies. While there is still much to learn about food allergies in adults, we know that there are some important differences that affect their management.
Food allergy in adults is a mix of persistent and new onset disease. So the fact that food allergy in children has become more persistent is resulting in an increase of allergies in adolescents and adults, as well.
Some food allergies that are diagnosed in children can persist into adulthood. Peanut and tree nut allergies are usually diagnosed in childhood, but, in adults, are more common than allergies to milk, egg or wheat that are more often outgrown. The following foods are known to be the most common food allergies in adults:
- Shellfish such as shrimp, crayfish, lobster and crab
- Tree nuts
- Fish such as salmon
U. S. estimates of allergy to fish are more than twice as high in adults as in children (0.5% versus 0.2%) and allergy to crustaceans (like shrimp) is five times more common (2.5% versus 0.5%).
One group of food allergies that begins to increase in older children and continues to do so during adulthood are those specific to plant allergens that “cross react” to pollen allergens. In several surveys of food allergy, these are the most common kind of food allergies that trouble adults.
The patterns and frequencies of these allergies can vary greatly with geography. The affected person first becomes allergic from exposure to airborne allergens, e.g. ragweed pollen, which then results in allergic symptoms from eating plant foods that contain allergens that cross react with ragweed. For example, ragweed-allergic individuals may develop reactions to related groups of foods such as melons. Often, the reaction only occurs when the food is eaten during the relevant pollen season. Ragweed allergic individuals may have no problems eating watermelon in July (no ragweed pollen), but then have significant symptoms in September, ragweed season. This is called oral allergy syndrome because symptoms are usually limited to the mouth and throat. It is usually caused only by fresh forms of the food.
People with oral allergy syndrome should see an allergist because reactions can be significant and could be confused or overlap with other food allergies. New blood tests are available now to determine when a person is at risk for more severe reactions to certain foods.
Reactions in Adults
Besides oral allergy syndrome, which is rarely associated with anaphylaxis, there is some evidence that food allergy reactions in adults tend to be more severe. Some factors we know of that can influence severity include:
- Asthma, particularly if it is not well controlled
- Alcohol consumption
- Some drugs including NSAIDS (aspirin and related drugs), beta-blockers and ACE inhibitors
These are factors that should be considered by patients together with their physicians in the management of their allergies in the context of their overall health.
FARE (Food Allergy Research and Education) has a webinar for adults with food allergies titled, “Safe and Sound: Relationships, Dating and Intimacy Challenges Associated with Having Severe Food Allergies”. You can also get insights from the study published in 2006 on the subject of kissing and how long peanut allergen, for instance, remains in the saliva after a person eats.
Alcohol and Epinephrine
Alcohol may increase the rate at which a food allergen is absorbed, therefore, resulting in a quicker onset of symptoms. If you have had an alcoholic drink and you need epinephrine, the epinephrine will still be effective; however, because alcohol can impair judgment and muscle coordination, it could affect your judgment in dosing or calling for help.
During OIT, the food allergen (a commercially available food mixed with a harmless food) is administered slowly, in small but steadily increasing doses, until the patient is desensitized to it. OIT has proven safe and effective in 80 percent of patients, provided that it is properly administered in a controlled setting.