When starting new medical treatments, many wonder about potential side effects. A common question about allergy shots is whether they cause weight gain. This article clarifies the relationship between allergy shots and weight changes.
Understanding Allergy Shots
Allergy shots, also known as allergen immunotherapy, are a long-term treatment designed to reduce or prevent allergy symptoms by gradually desensitizing the body to specific allergens. These injections contain tiny amounts of the substances that trigger allergic reactions, such as pollen, dust mites, mold, or insect venom. The immune system is exposed to these allergens in increasing doses over time, prompting it to develop tolerance rather than an inflammatory response.
This process trains the body to produce different antibodies, specifically immunoglobulin G (IgG), which can block allergens from attaching to cells that cause allergic reactions. The treatment typically involves two phases: a “buildup phase” with frequent injections (one to three times a week for six to ten months) and a “maintenance phase” with less frequent shots (about once a month for three to five years or longer). Over time, this immunotherapy aims to reduce the need for allergy medications and provide lasting relief from symptoms.
Allergy Shots and Weight Changes
Allergy shots do not directly cause weight gain. Unlike some antihistamines that can increase appetite or decrease activity levels, allergy injections work by exposing the immune system to allergens to build tolerance, rather than by blocking histamines. They do not contain calories or affect the body’s weight control centers in the brain.
Common side effects of allergy shots are typically localized reactions at the injection site, such as redness, swelling, or itching, which usually resolve within a few hours. Systemic reactions, while less common, can include sneezing, nasal congestion, hives, or, in rare severe cases, anaphylaxis, a life-threatening reaction requiring immediate medical attention. However, weight gain is not a recognized direct side effect of allergy immunotherapy.
Other Factors Affecting Weight During Treatment
While allergy shots themselves do not directly cause weight gain, other factors can influence weight during the period of treatment. Chronic inflammation associated with allergies can lead to increased fluid retention, which might be perceived as weight gain. This inflammation can also interfere with hormone regulation, affecting hunger and metabolism.
Certain allergy medications, particularly oral corticosteroids like prednisone, are known to cause weight gain through increased appetite and fluid retention. If a person is taking such medications for acute allergy symptoms in conjunction with allergy shots, this could contribute to weight fluctuations. Severe allergy symptoms can also lead to reduced physical activity, and poor sleep due to allergies can affect hunger hormones, both of which may indirectly influence weight.