Health Tips

"Why does my skin itch every time I eat certain foods?"

What’s a food allergy?

Food allergy occurs when an individual’s immune system mistakenly perceives the ingested food to be harmful to the body hence producing specific antibodies (immunoglobulin E, IgE) in an attempt to thwart the “invasion”. The onset of food allergy reactions is rapid, typically occurs within minutes to 2 hours after food ingestion. Nevertheless, it should not be mistaken as food intolerance which is a condition associated with difficulty digesting or breaking down of a certain food.

“It may sound kind of odd, but I was fine the first time I ate it. Then, I had these horrible rashes the second time around. Sounds weird, isn’t it?”

That sounds like a food allergy. Like many other allergy reactions, you will generally not have any symptoms during the first exposure although an insidious sensitization process is brewing inside the body. The immune system is starting to recognize the food protein/particle as being ‘foreign’ in the initial exposure.

The immune system mounts its defense by building up more antibodies in preparation for another bout of perceived ‘invasion’.

These antibodies are deployed against the allergen as soon as you eat the same food again which explains the ‘flare up’ reaction during subsequent exposure. Even a tiny amount of the food can trigger immunologic reaction leading to the release of a huge amount of histamine that affects the skin, gastrointestinal tract, airways, and cardiovascular system.

As a result, an individual may experience a host of unpleasant and sometimes severe symptoms such as:

• Itching/tingling sensation to the mouth and throat
• Swelling of lips, tongue, throat and face
• Runny nose, coughing, wheezing, breathing difficulty
• Skin rashes, hive and itch
• Excessive intestinal gas, bloating, abdominal pain/cramp and diarrhea
• A sudden drop of blood pressure which can lead to dizziness, loss of consciousness and even death if organs shut down.

Body rashes (also known as hives) due to allergy.

Severe allergic reaction (also known as anaphylaxis) requires immediate medical attention!

It is worth pointing out that, the severity of allergic reactions can be unpredictable! An individual may develop only mild symptoms (mild itching) on one occasion but life-threatening anaphylaxis with the next. Hence, the best advice is to avoid the allergy-triggering food altogether.

Common foods that can trigger allergy include:

• Milk
• Nuts (peanut and tree nuts)
• Eggs
• Food with high biogenic amines (banana, chocolate, tomato)
• Certain red meat
• Seafood (fish, shellfish, mollusks)
• Wheat
• Soybeans

I think I have a food allergy. What should I do?

• Speak to your doctor and get some diagnostic tests done in order to confirm this.
• Avoid specific food (or related ones which can be cross-reactive) known to cause allergy reaction in you even if it's mild.
• Always check the food content (food labels or asking the preparers) to ensure the absence of known allergens.
• In mild cases, check with your doctor or pharmacists on the appropriate antihistamines that can be used to alleviate the symptoms. As mentioned previously, immediate medical attention should be sought in the event of life-threatening anaphylaxis.

To a healthy and safe diet!

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References:

1. Brill H. Approach to milk protein allergy in infants. Canadian Family Physician. 2008;54(9):1258-1264.
2. Ikemoto C, Tamagawa-Mineoka R, Masuda K, et al. Immediate-onset anaphylaxis of Bacillus subtilis-fermented soybeans (natto). J Dermatol 2014; 41:857.
3. Kamdar TA, Peterson S, Lau CH, et al. Prevalence and characteristics of adult-onset food allergy. J Allergy Clin Immunol Pract 2015; 3:114.
4. Lomer MC. Review article: the aetiology, diagnosis, mechanisms and clinical evidence for food intolerance. Aliment Pharmacol Ther 2015; 41:262.
5. Monsbakken KW, Vandvik PO, Farup PG. Perceived food intolerance in subjects with irritable bowel syndrome– etiology, prevalence and consequences. Eur J Clin Nutr 2006; 60:667.

In collaboration with Dosing Health.

Written by

John Tiong