A skin rash can result from either eating or touching highly acidic foods, such as tomatoes, peanuts or citrus fruits. If you develop a skin rash after you consume the food, you may have an allergy to that specific food. If you develop a rash after you have direct contact with the food, the rash is considered contact dermatitis, a form of eczema. Any time you experience an adverse reaction from a food or substance, talk with your doctor to determine the cause and best treatment options.
A food allergy occurs if you immune system is hypersensitive to certain proteins found in certain foods. The body mistakes the proteins as harmful substances and begins to defend itself by creating antibodies, according to the Mayo Clinic. The antibodies fight off the proteins and trigger production of histamine in the mast cells. This increased level of histamine causes inflammation and irritation in different parts of the body. If histamine levels rise in the skin, a rash can develop in the form of hives or eczema.
Contact dermatitis is a form of eczema that is triggered by touching foods. The most common foods that can trigger contact dermatitis are highly acidic fruits and vegetables, such as oranges, kiwi and celery, according to the Australasian Society of Clinical Immunology and Allergy. The acid or other ingredients from the fruits or vegetables cause the skin to become irritated, leading to an eczema flare-up.
Symptoms will develop within minutes of eating or touching highly acidic foods. Common symptoms for an allergic skin rash, including contact dermatitis are itching and swelling in the skin, skin inflammation, localized swelling, skin lesions, redness and tenderness in the area of the affected skin.
If the rash is the result of a food allergy, you may experience other symptoms, such as asthma, digestive complications and nasal congestion. Asthma symptoms that can develop include shortness of breath, chest tightness and wheezing. You may experience vomiting, diarrhea, nausea and stomach cramping. Nasal congestion can lead to postnasal drip, sinus pressure and headaches.
If you develop hives as a result of ingesting a food that is accompanied with dizziness, feeling faint, swelling in the throat and an increased heart rate, call 911 immediately. These are all symptoms of anaphylaxis, a life-threatening allergic reaction.