Allergy

Updated 23 June 2014

When pollen is in the air

Spring is in the air. And so are a thousand allergy-causing pollens. This is bad news for the growing number of people suffering from allergies whether it is hay fever, asthma, eczema or other forms of allergies.

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Spring is in the air. And so are a thousand allergy-causing pollens. This is bad news for the growing number of people suffering from allergies whether it is hay fever, asthma, eczema or other forms of allergies.

An allergy can start at any age. Children are most vulnerable to allergies, especially hay fever (allergic rhinitis). Boys younger than 10 years are twice as likely as girls in this age group to have symptoms of allergies to airborne substances. And there is no indication that children actually outgrow the tendency to be allergic. They may outgrow a specific allergy but develop another one. At least the reactions tend to subside with age.

What happens during an allergic reaction?

“Allergic” people have a hyper-alert immune system that reacts intensely to allergens, which are harmless to 80 percent of the population. During an allergic response, a series of reactions are set in motion, starting with the production of specific antibodies and culminating in the release of histamine and other chemicals in the blood. These chemicals may cause dilation of blood vessels and constriction and swelling of the airways, leading to itchiness, runny nose, sneezing, wheezing and other symptoms.

Different allergens may evoke different symptoms. Allergens in the air may trigger allergic reactions in the eyes (allergic conjunctivitis), nose (hayfever, also known as allergic rhinitis) and lungs (asthma), while ingested allergens may cause symptoms in the mouth, stomach and intestines such as diarrhoea and even hives. In severe cases, allergens can cause a drop in blood pressure, shock and even loss of consciousness.

pollen flowers


Do you have a mild, moderate or severe allergy?


Mild reactions are restricted to a specific area of the body and do not spread to another part of the body. Mild reactions include an itchy, red skin rash, itchy and watery eyes, congestion, sneezing and a runny nose.

Moderate reactions include symptoms that spread to other parts of the body. This may include itchy, red bumps (hives) all over your body, difficulty breathing or other moderate asthma symptoms. These symptoms should not be ignored.

A severe reaction (known as anaphylaxis), is rare, but a life-threatening emergency. It affects the whole body. It may begin with symptoms like itchy eyes, only to progress within minutes to serious swelling of the airways that can make breathing and swallowing difficult, and to stomach cramps and diarrhoea, and even confusion and dizziness due to a sudden drop in blood pressure. Anybody with these symptoms needs emergency treatment.

The major allergens

Pollens. Grass pollens are the most common allergy-causing pollens, especially those shed by Bermuda grass, rye grass, kikuyu and love grasses. Allergies from tree pollens, particularly the oak, acacia, olive, eucalyptus, willow, cypress and plane trees are common. Pollens from the weeds mugwort and sheep sorrell may also cause allergies.

House mites. You cannot see this eight-legged creature with the naked eye. It lives in warm, humid places such as human bedding and upholstery and is a common asthma trigger.

Pets. Skin flakes, dried saliva, or the urine of cats, dogs, rats, mice, guinea pigs, rabbits, hamsters, birds, horses, cows, chickens, ducks and geese can cause allergies. Cat allergens can stay airborne for months and affects nearly half of asthma sufferers.

Bird allergies. Birds carry allergy-provoking mites, moulds and pollen on their feathers. Budgie droppings can release proteins into the air that induce insidious lung problems and asthma.

Food allergies. Nearly 90 percent of life-threatening food reactions are caused by eight foods: peanuts, eggs, milk, wheat, tree nuts, soy, fish and shellfish, according to the American Federal Drug Administration (FDA). The symptoms may range from swelling of the lips, face and tongue, stomach cramps, vomiting, diarrhoea, hives, rashes, eczema, perspiration and dizziness to wheezing and severe breathing problems and even death. An allergic reaction to food usually occurs within half an hour of eating it, but can also occur within only five or 10 minutes or after four to six hours.

Cigarette smoke. Even passive smoking is linked to asthma.

Drug allergies. The antibiotics penicillin and amoxill, sulphur-containing medication, barbiturates used for epilepsy treatment, anticonvulsants, insulin, some local anaesthetics, and dyes injected into blood for X-ray purposes, may cause allergic reactions.

Venoms. It is thought that people who have allergies such as food, drug or respiratory allergies are more prone to insect sting allergies. The venom in the stings of bees, wasps and hornets may trigger an allergic response. It is best for these people to carry a single-dose injection kit of adrenaline. Injecting themselves with the adrenaline will help counteract and alleviate allergic symptoms until they can receive medical attention. (Note that allergies to cockroach droppings are not uncommon.)

Parasites. Acsaris (mainly in the Western Cape) and Schistosoma (mainly in the north of the country).

Moulds. Cladosporium fumigatus and Alternaria alternata in old, damp homes.

Latex. Rubber gloves, condoms and other latex products. Interesting facts and stats about allergies

  • 20%: Percentage of people suffering from some form of allergy.
  • 240: The minimum number of identified allergens, some rare and others very common.
  • 10 000: The estimated number of house dust mites in the average bed, according to the Allergy Society of South Africa.
  • 2 %: Percentage of adults truly allergic to certain foods, according to the FDA.
  • 2 – 8 %: Percentage of children truly allergic to certain foods, according to the FDA.
  • 1/44 000: The fraction of a peanut kernel that may prompt an allergic reaction in highly allergic people.
 

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Allergy expert

Dr Morris is the Principal Allergist at the Cape Town and Johannesburg Allergy Clinics with postgraduate diplomas in Allergology, Dermatology, Paediatrics and Family Medicine dealing with both adult and childhood allergies. obesity and diabetes societies and runs a trial centre for new drugs.

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