We have, over the years, seen many cases of asthma having their symptoms only during the Diwali season. Our investigations have shown that it is not the Diwali weather which is detrimental , to the health of these people. It is the customary cleaning of the house among north Indians at this time which raises so much dust that those who are allergic to it, experience symptoms of asthma.
WHAT IS HOUSE DUST?
House dust consists of many things. It has in it the dust that comes from clothes, furnishings, bedding, and pillows; from pets, if there are any; from the parts of the insects in the house; the fungi that grow everywhere; from food remnants; from the human skin and hair; it is also contains the outside dust which comes in with the wind. If the furniture, furnishings, beddings, carpets and rugs are old, more house dust is produced from them. If such house dust is not normally visible it can be seen in the shafts of sunlight that enter a room. These particles gradually settle down in the form of house dust.
MITES IN HOUSE DUST
People allergic to house dust were found not to be allergic to each of the above-mentioned constituents. The true nature of house dust antigen remained a mystery till 1964, when a Dutch research team demonstrated that it was the common house dust mite called dermatopagoides pteronyssinus which caused the allergenicity in house dust. Later on, other allergenic mites were also discovered in the house dust. In some samples of house dust over 200 mites in 1 gm of it have been found.
Mites feed and grow on the constituents of house dust. The common house mite, is relatively small (about one-third of a millimetre in length). It can become airborne during bedmaking, and is present in great numbers in and on mattresses. It grows best, though very slowly, in high humidity (80 per cent), at an optimal temperature of 25°C, and preferably on human dander. It prefers high humidity and moderate termperature.
Improvement in some asthmatic patients on admission to hospital may be the result of reduced exposure to the allergens associated with the house mite. Also aggravation of asthma on going into the bedroom or while in bed may reflect the larger amounts of it in the bedding and the bedroom.
Allergy to house dust is quite common. In a study conducted by me, skin tests were done against different pollens, fungi and dusts on 462 patients of asthma. It was found that 286 (61.9 per cent) were positive to house dust either or in combination with other allergens.
Those who are allergic to house dust, must avoid it. The bedroom must be scrupulously clean and uncluttered. All upholstered furniture, rugs, window drapes, and dust-catching ornaments must be removed. The almirah should contain only the patient’s current clothing and should be as dust-free as the room itself. Mattresses and pillows should be made of foam rubber. The room should be cleaned with a damp cloth.