Garlic allergies manifest as an upset stomach, including diarrhea, constipation, vomiting, nausea and bloating, according to Allergysymptomsx.com. Other symptoms include itching, swelling and redness around the mouth; eczema; and a runny nose. Allergy symptoms manifest quickly after garlic is eaten and can be extremely severe.
Garlic allergies occur when the immune system attacks the protein in garlic, releasing histamines. People with garlic allergies often have onion allergies as well, states Allergysymptomsx.com. An elimination diet diagnoses individuals with garlic allergies at home. Doctors perform a skin prick test or blood test for definitive diagnosis.
Symptoms vary in severity. Diarrhea and vomiting are not inherently risky, but prolonged suffering can result in dehydration and death. Runny noses can seem mild, but they occur because of the swelling of the nasal passage, which stimulates increased mucus production, according to Allergysymptomsx.com. In more severe reactions, this blocks the airways and stops breathing. The sudden drop in blood pressure leads to dizziness and numb limbs.
Garlic allergies are usually easily treated with antihistamines. For people who suffer more severe reactions, doctors prescribe steroids or epinephrine to prevent anaphylactic shock, explains Allergysymptomsx.com. Avoiding garlic is difficult, however, especially when eating out. Furthermore, manufacturers are not required to list garlic as an allergen or ingredient on labels, making cooking more difficult.