When the body's immune system reacts to normal substances, such as tree pollen or cat hair, allergic symptoms develop in the skin, lungs and internal tissues. Although caffeine is found mostly in food products, such as coffee and chocolate, it is also a drug product that has distinct effects on breathing and blood vessels. Changes in the level of caffeine in the body can affect allergy symptoms in some people.
Environmental Allergy Symptoms
When histamine increases as a result of an allergic contact, the entire body reacts. Itchy eyes and nose, cough, wheezy breathing and itchy skin occur because of greater histamine levels in the skin, lungs and internal mucous membranes. The body experiences an inflammatory reaction to the allergen that can lead to a stuffy nose, headache and sinus pressure as well.
Caffeine Effects on Breathing
Caffeine is closely related to theophylline, a prescription drug used to improve breathing, and caffeine itself has been experimentally used to control some types of asthma. When wheezing occurs during an allergic reaction, the air passages are tightened, and caffeine appears to open these airways. However, caffeine effects from food are variable and likely short lived.
Cardiac Effects of Caffeine
Caffeine can cause a jittery sensation, particularly if too much is ingested at one time. This side effect results from an increased heart rate and only occurs for a short time after using caffeine. More pronounced effects on blood vessels and the heart occur because of regular caffeine use, when the cardiac system adapts to the level of caffeine normally in the diet. When caffeine is removed, headaches are likely and could worsen headaches that already exist as a result of allergic reactions.
Caffeine Dosages and Warnings
Caffeine as a prescription product is dosed by weight for infants who have trouble breathing, but caffeine as a food product cannot be similarly used at consistent dosages. Although caffeine may appear to improve lung symptoms of allergic reactions, changing caffeine levels in the body can also make allergies worsen. Environmental allergies should be treated by making lifestyle changes and taking medications with health care professional approval rather than by increasing the amount of caffeine in the diet.