Dr Jonathan Chong
ANN/THE STAR – Food allergies are defined as adverse reactions to certain types of food due to underlying mechanisms mediated by the immune system.
Such allergies can develop at any age, although most tend to first appear during childhood.
While any food can theoretically trigger an allergic reaction, a select few foods are often responsible for most of these reactions, with the most common food groups being seafood and tree nuts.
However, there are a number of uncommon allergies that are becoming more recognised in recent years, including red meat allergy syndrome and pancake syndrome.
Red meat allergy, also known as “mammalian meat allergy” or “alpha-gal syndrome”, can develop after a bite from the Lone Star Tick found commonly in the southeastern United States (US).
The tick bite can transmit a type of sugar molecule called alpha-gal, which can cause some people’s immune systems to produce allergic reactions to certain meats such as beef and lamb, as well as other mammalian products like milk and gelatin.
The reactions can range from mild to severe, and there is currently no known cure.
Pancake syndrome, also known as oral mite anaphylaxis, can occur after ingesting certain wheat or corn products contaminated with specific types of dust mites.
Broadly speaking, food allergies can be classified into two categories: immunoglobulin E (IgE)-mediated or non-IgE mediated, although some reactions can pose characteristics of both mechanisms.
In IgE-mediated reactions, the onset of symptoms is fairly short, usually developing within 10 minutes to four hours from the time of ingestion of the food allergen.
These symptoms can involve multiple systems in the body, including:
– Skin, eg hives, swelling, itching and flushing.
– Respiratory system, eg shortness of breath, wheezing.
– Circulatory system, eg lightheadedness, low blood pressure, fainting spells.
– Digestive system, eg nausea, vomiting, diarrhoea, abdominal cramps.
Symptoms for non-IgE-mediated reactions however, tend to appear later. They are also usually localised to the digestive system and/or skin.
Mild allergic reactions, such as localised rashes, may be self-medicated with antihistamines, and may not require medical attention.
Severe cases, otherwise known as anaphylaxis, may involve multiple systems, causing skin rashes, eye and throat swelling, chest tightness, dizziness and palpitations.
They are potentially fatal, especially if left untreated or if treatment is delayed. In such cases, self-treatment with medications such as antihistamines is of limited benefit at best, as they do not alleviate airway obstruction.
Anaphylaxis is also often accompanied by a condition known as anaphylactic shock, where the body’s tissues and cells do not have sufficient amounts of oxygen to function. If an individual is suffering from shock, it is a medical emergency and it is essential that they be transported to the hospital as soon as possible, so that timely treatment and monitoring can
be initiated.
If you suspect that you are experiencing a moderate or severe allergic reaction, it is advisable to seek immediate medical attention.
The symptoms of an allergic reaction can initially appear to be quite mild, but they can escalate rapidly within a very short period of time, and it can be difficult to predict when an allergic reaction might take a turn for the worse.
