Food allergies are known to cause digestive complications, skin rashes and asthma, but in some cases food allergies can lead to fatigue, sore muscles and fever. Fatigue and fever are not a direct result of the food allergy but are rather the symptoms of another condition caused by the food allergy. For example, sinus headaches are a common result of an allergic reaction to food that can cause fatigue from sinus pressure. Discuss your symptoms with your doctor to ensure the symptoms are the result of a food allergy and not another condition.
A food allergy occurs when your immune system reacts in an exaggerated manner to the proteins found in specific foods. PubMed Health explains that a food allergy causes your immune system to defend the body by producing immunoglobulin E -- or lgE -- antibodies. These antibodies are triggered as a mistake and cause a chain reaction in the body that leads to common allergy symptoms. Common symptoms of a food allergy include shortness of breath, hives, diarrhea, nausea, vomiting and nasal congestion. The most common foods that cause an allergic reaction include eggs, milk, peanuts, tree nuts, fish, soy and wheat.
Fatigue from food allergies is the result of inflammation in the sinus cavity. Sinus congestion is a common symptom of a food allergy that causes swelling in the nasal passages that restricts the ability to breathe and discharge mucus through the nostrils. This makes pressure build up in the sinus cavities, leading to pain and tenderness throughout the face. The pressure that builds at the back of your eyes can make you feel fatigued, as does pain in your ears, forehead, cheeks and upper teeth.
Soreness in the muscles is the result of increased histamine levels throughout the body. After the immune system creates IgE antibodies, mast cells located in soft tissue produce histamine, according to the American Academy of Allergy, Asthma and Immunology. Histamine is a substance in the body that guards the body from developing infection. Excessive amounts of histamine created during an allergic reaction lead to swelling, irritation and inflammation in soft tissues. Your muscles in your lungs, stomach or joints may become sore shortly after eating a food allergen.
According to the MayoClinic website, fever is never a symptom of an allergic reaction. A fever resulting from a food allergy is most likely caused by a secondary infection, such as sinusitis. A sinus infection may develop from a food allergy, and this can cause a fever. Talk with your doctor to determine the cause of the fever.