Diagnosing Allergies: What to Expect from Allergy Testing

Allergy Conditions

General – Environmental Control Measures

Written by Dr A I Manjra

 

(I) House Dust Mite Control

 

House dust mites are the commonest allergens along coastal areas of South Africa. House dust avoidance measures should be instituted by asthmatics patients with allergic rhinitis and atopic eczema who are proven to be allergic to mites (see diagram).

Mite avoidance measures

The major mite allergen is Der p 1 located on mite faecal pellet particles. Mites are mainly found on bedding and carpets therefore avoidance measures should concentrate on these two areas.

BEDROOM   EFFECT   1) Remove carpets   Reduces mite reservoir levels.   2) Remove books, fluffy toys, thick curtains   Reduces dust accumulation and Airborne mite levels.   3) Regular hot washing (every 1-2 weeks) of fluffy toys (if unable to do 2).   Kills mites – removes allergens   4) Cover pillow or mattress with plastic or polyurethane cover.   Isolates mites and prevents re- Infestation of bedding   5) Regular (weekly) hot washing (>55° C) of bedding and mat tress and pillow covers.     Kills mites – removes allergen

House

1) Weekly vacuum cleaning of carpets and upholstered furniture   Removes surface dust faecal pellets but not live mites.   2) Decrease indoor humidity (air conditioner in summer, heater in winter.   Control mite growth   3) If possible, remove all carpets   Reduces mite reservoir levels   Acaricides Acarosan (Noristan) Benzyl Benzoate Actomite (Searle)   Kills mites on carpets but no effect on mattresses Kills mites in laboratory but not proven to work in domestic environment.   Acarosan should be vigorously applied to carpets and left on for more than 12 hours before vacuuming. This should be repeated every 3-4 months. Patient leaflets are available from ALLSA Resource Centre.

(II) Mould Control

 

Mould control is very difficult. There are a few measures that may control mould exposure. Moulds thrive in warm humid environments and spore counts peak in spring and autumn. In South Africa important moulds are:-

1. Aspergillus: Found in damp homes i.e. basements and bathrooms. Grows on cereal grains.
2. Alternaria: Found on decaying vegetation and also in damp indoor environments.
3. Cladosporium: Found indoor and outdoor.
4. Epicoccum: Found on decaying vegetation.

Indoor mould control

1. Reduce indoor humidity: Shower curtains, plumbing fixtures, leather goods and draperies become quickly contaminable if not adequately ventilated. Therefore regularly inspect these areas. Adequately air and ventilate the kitchen and bathroom as a matter of necessity.
2. Limit indoor plants
3. Do not leave fruit and bread lying around since these become rapidly contaminated. Rubbish bins should be emptied and cleaned regularly.
4. Tiles, plumbing fixtures, shower curtains, and bathroom ceilings should be regularly inspected and wiped down with Jik, Milton or Lysol.
5. House dust mite avoidance measures are also useful in reducing fungal spore levels since these spores are part of house dust.
6. Mould allergic patients must avoid entering damp basements or homes known to be damp or poorly ventilated.
7. Asthmatics should regularly clean their nebuliser tubings with detergents to avoid mould contamination.

Outdoor mould control

1. Mould sensitive patients should avoid contact with decomposing leaves, grasses and grains.
2. Raking of leaves should be avoided.
3. Avoid exposure to compost, hay, vines and barnes.
4. Avoid entering areas of deep shade or heavy vegetation.
5. An industrial mask should be worn when exposure cannot be avoided if moulds are an occupational hazard.

(See also Appendix VII).

(II) Pollen Allergy

 

Grass, tree and weed pollens are a major problem along non-coastal areas of South Africa. Pollen allergy causes Hay fever, Seasonal asthma, Allergic conjunctivitis and Atopic eczema. Pollen calendars are available. (Plates 4,5,6 on pages 126-131).

Pollen is almost impossible to avoid particularly during pollination seasons. There are some measures that may help in reducing pollen exposure.

1. Avoid entering open fields on windy spring days.
2. Keep car and bedroom closed on windy spring days to prevent pollen entering the indoor environment.
3. Avoid grass cutting. If this is not possible wear and industrial mask. Keeping grass short also limits pollen release.

(III) Pet Allergy

 

Pet allergic patients can suffer allergic rhinitis, asthma and conjunctivitis. Cats are the most allergenic of domestic pets and cat allergen (Fel d 1) can be extremely difficult to remove from household even months after the cat has been removed. Different animals shed allergens from different areas of their bodies.

ANIMAL   ALLERGEN SOURCE   Cat   Saliva   Dog   Skin, saliva, urine   Rabbit   Saliva, urine   Horse   Skin   Cow   Skin   Hamster   Skin   Rat   Urine   Mouse   Urine

 

Avoidance measures

The obvious method is to remove the animal from the domestic environment. However patients are not always willing to do this. Special measures therefore need to be taken with regard to pets.

Cat Allergen Avoidance

1. Removal of cat. Follow this with rigorous, intensive vacuum cleaning.
2. If cat removal is not possible, wash the cat weekly and institute similar measures as dust avoidance measures.

Dog Allergen Avoidance

 

The dog should be removed or kept strictly outdoors and away from the allergic patient.

 

 

(IV) General Measures for Asthmatic Patients

1. Avoid tobacco smoke.
2. Avoid exposure to dust and other irritants such as hair sprays, insect sprays, paint and exhaust fumes.
3. Avoid contact with people with viral upper respiratory infections.
4. Avoid drinks with preservatives i.e. sulphites, benzoates and monoglutamates.