Women are more allergic to roaches than men

In what may trigger a new gender debate, doctors at Kenyatta National Hospital find women more allergic to cockroaches than men.

The ear, nose, and throat specialists studied 81 adult patients with allergic rhinitis and found women at higher risk of cockroach allergy than men.

“In this study we found a cockroach allergy was more common in women than men, with positivity being 55.1 per cent in women and 25 per cent in men,” say the doctors.

Allergic rhinitis is a condition that triggers a runny or stuffy nose, sneezing, red, itchy, and watery eyes, or swelling around the eyes.

It is also known as hay fever and linked to asthma, with experts saying it normally lowers the patient’s quality of life.

It may also contribute to learning difficulties, sleep disorders, fatigue, and associated with ear problems.

The KNH study team, led by Wangari Thinguri, who is also a lecturer at the University of Nairobi, suggests that the higher cockroach allergy in women may be due to their homemaker roles.

Women, Dr Thinguri says, tend to be the ones who do more of the chores at home, including more time spent in the kitchen, where the cockroaches normally reside.

“This would lead to higher exposure in women than men, hence the higher sensitisation in the women compared to men.”

Cockroaches and babies

Exposure to cockroach allergens in the first three months of life has been associated with repeated wheezing and asthma. They get affected when they breathe-in the insects’ saliva, feaces or shed body parts that may have been kicked into the air.

Generally, though allergic rhinitis at younger ages is more common in boys than in girls, in adulthood it is approximately equal between men and women.

The new study, however, was much larger than cockroaches, as it primarily wanted to find out the different causes of allergic rhinitis in patients seeking care at KNH.

The doctors, including Jonh Ayugi and Samuel Nyagah of the University of Nairobi and KNH respectively, investigated how the 81 patients reacted to five common allergens. These included house dust mite, mould, cockroach, and cat dander mainly found indoors, as well as grass pollen – an outdoor allergen. In this case, they referred to Bermuda grass (also called couch grass) which is common in Kenya.

Majority of the patients, 77 per cent, were sensitive to dust mite, followed by moulds, 57 per cent and cockroaches at 43 per cent.

“The prevalence of sensitization to cat dander and grass pollen was 40 per cent and 30 per cent respectively,” says the study in the current issue of the East and Central Africa Journal of Otolaryngology, Head, and Neck Surgery.

Dust mites in your house

Dust mites, which are related to ticks and spiders, are too small to see without a microscope. They eat skin cells shed by people and are likely to be found in bedding, furniture and carpets.

Some studies indicate many people with dust mite allergy also experience signs of asthma, such as wheezing and difficulty in breathing. Dust mites can be reduced by ensuring that you clean/vacuum the carpet regularly, clean the curtains and bedding weekly and use dustproof bed covers.

The KNH study also found that some patients were sensitive to more than one type of allergen. A small number was found sensitive to all five allergens.

Half of the patients experienced persistent, moderate to severe rhinitis, with a significant number also co-infected with asthma and eczema.

Asthma and eczema

Eczema (or atopic dermatitis) is a common, long-lasting condition that makes the skin itchy, shiny or red and irritated. It is most common in children. It has no cure and maybe accompanied by asthma.

Most children, says a brief by Gertrude’s Children’s Hospital in Nairobi, will outgrow atopic eczema by the time they are 10, although a few live with it into adulthood.

The KNH study found a link between grass pollen and patients with eczema. “Sensitivity to pollen among patients with eczema was 60 per cent compared to 25.4 per cent among those without eczema.”

An earlier study on the prevalence of asthma, allergic rhinitis, and eczema in children aged between 13 and 14 in the Rift Valley region found the diseases to have increased significantly within the six-year study period.

The study by Moi University, Eldoret, found the three conditions to have increased in rural and urban children, though much higher in the latter.

The increase, they suggested, is being driven by environmental factors such as air pollution and change in diets. “There was an increase in the prevalence of asthma over the study period, possibly due to affluent lifestyles in many families.”

Dr Rose Kamenwa, a consultant pediatrician at Aga Khan University Hospital, partly blames the increase of childhood allergies to rising caesarean births.

C-section births, she says, raise the risk for allergies because the infants do not get into contact with protective bacteria found in the normal birth canal.

She cites data in Norway, which showed C-section children having a 52 per cent increased risk of asthma compared with those of vaginal delivery’s 19 per cent risk.