THE ABCs OF ALLERGIC REACTIONS

Around one third of South Africans will suffer from allergic disease during their lives, according to Allergy Foundation South Africa. Here’s how to tell if you’re one of them, and what to do about it.

Stuffy nose, itchy eyes, hives and swelling on the body – Dr Tshegofatso Mabelane, an allergist practising at Mediclinic Morningside, says these are some of the most common allergic reaction symptoms that people experience.

But allergies can also manifest in other ways serious ways, she warns, affecting the:
– Abdomen – sustained pain, vomiting or diarrhoea
– Chest – cough or wheezing
– Heart – increased heartbeat

A severe allergy could even result in death following anaphylaxis.

Intolerance vs allergy

“In all cases, it’s vital to distinguish between an intolerance and an allergy,” Dr Mabelane says. Although you may have experienced some of these symptoms, it’s only if your immune system is involved in the body’s response to a stimulant that they’d be considered signs of an allergy. “This response is triggered by the production of IgE, an antibody that usually fights parasites. In allergic people, IgE goes into overdrive around allergens – substances like pollen, dust mites, cat or dog food, pet hair, certain foods (cow’s milk, soy, egg, fish, wheat, peanuts and tree nuts), bee stings, or even certain medications.”

It’s equally important to distinguish between immediate allergic reactions (which manifest within two hours of exposure to the allergen) and delayed reactions. Delayed allergic reaction is typical in the case of allergens like medication, and may only present over two hours, days or even weeks after exposure.

Stuffy nose and itching eyes often occur in response to environmental allergens.

Acute reaction vs chronic disease

Finally, says Dr Mabelane, a difference also exists between acute allergic reactions and chronic allergic inflammatory diseases, where often the body’s T helper 2 cells (Th2) come into play. These diseases typically include asthma, hay fever or eczema.

Long-term eczema shouldn’t be confused with an acute allergic rash or urticaria, which presents as hives that typically disappear within 24 hours and do not leave a scar, and which is prompted by an autoimmune response. In contrast, eczema, a thickening of the skin that usually presents in areas like the elbows, knees, face or hands, is caused by multiple factors, such as the immune system. Here, genetics and the environment are responsible.

I think I have an allergy – now what?

If a person has one parent who presents with allergies, they have a 50% chance of being atopic (sensitive to allergens). This increases to 75% if both parents have allergies. “But there is no way of predicting if a person will suffer from allergies without allergy testing,” says Dr Mabelane. “Even then, allergy testing should only be conducted if the individual has shown clear allergy symptoms. Also, a person who has allergic parents will already have inherited a tendency to produce IgE, so tests may show a false positive.”

A variety of tests are available, she explains:
Skin prick tests entail introducing commercially produced allergens (like pollen) to the skin through a small scratch, created with a lancet. The test is not painful; it may even be performed on infants as young as three months, Dr Mabelane assures. A positive response to the allergen will produce a small hive on the skin.

Blood tests seek to identify the presence of IgE in response to certain allergens. Tests for specific allergens tend to be more accurate than panel tests. “It’s important that blood tests are conducted by an experienced allergist, as they tend to give false positives,” says Dr Mabelane.

Challenge tests do just that – challenge the immune system by exposing the individual to known allergens. This is usually done to confirm whether a person is still allergic to a substance like penicillin, and, again, must be conducted by an allergist who will follow strict protocols to ensure patient safety.

Specialist allergy treatment, or immunotherapy, may continue over a number of years.

Can my allergy be cured?

The good news is that some allergies can be cured through immunotherapy. This is no quick fix, Dr Mabelane warns: it may take as long as three to five years, with patients receiving incremental doses of commercially made allergens (either in droplet or injection form) until the patient is able to tolerate the substance. There should be a marked difference after one year of treatment, although the dosage may be sustained for a further two years to ensure the allergy does not return, or to prevent the development of similar allergies.

How to find help

If you have experienced allergy symptoms, consulting an allergist may help save your life. Visit mediclinic.co.za to find a specialist in your area.

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