Types of Allergies

As written earlier, allergy is of different types depending on the mechanism of action and agent (allergen) For layman it will be easier to comprehend if( allergy) is classified based on the causative agent. Thus the types of allergy may be classified as given below;-

1. Dust Allergy

2.Food Allergy

3. Drug Allergy

4. Insect Allergy

5. Skin Allergy

6. Allergy due to other substances

Dust Allergy

Dust allergy refers to allergic symptoms caused by inhaling (breathing in) certain microscopic particles found in the environment surrounding us. These allergens (also called aeroallergens) may be foud either at home, in our place of work or while travelling from one place to another. The common aeroallergens are as follows;

1.Dust, smoke fumes and gases emitted by polluting vehicles, industries and factories are most common areoallergens in India

2.Climatic conditions like high humidity, sudden changes in temperature especially from warm to cold and smong formation are also important factors causing allergic symptoms.

3.Active and passive smoking is equally responsible for causing allergy and other symptoms of the respiratiry system

4.pollen grains of different plants suspended in air especially on windy and rainy days

5.Fungi and moulds found in damp and moist areas also cause allgergic diseases.

6.Dust mite found  at home that collect in the mattresses, furniture, carpets and rugs bedding draperies clothes and floor, which are inhaled while dusting or cleaning the house.

7. Inhalation of insect parts and droppings of cookroaches, flies moths butterflies, rats,mice bed bugs mosquitoes, houseflies etc.

8.Animals allergen in the from of epithelial scales (dander),hair or feathers of animals like dogs cats cattle horse sheep gost duck etc.

9.Occupational allergens like silica, asbestos lead nickel coal cotton wool, fibres,  paints varnishes, resind grain flour formaldehyde insecticides, pesticides dyes drugs spices printing ink etc.

Food Allergy

Food are mainly composed  of proteins, carbohydrates and lipids. Usully, the manjore food allergens are the glycoproteins foud in the food .

1.About 2-3% of infants  suffer form Cow ' s milk allergy which is the most common food allergy of childhood This seems logical since cow 's milk formula is usually the first foreign substance a baby consumes and also the digestive and immune systems of the infant are not fully developed Most children outgrow milk allergies by the age of age of four and food allergies that develop after this ade are usually premanent The major allergens in milk are the caseins and the whey protein -beta lactoglobulin The milk from goats and sheep has almost similaer proteins as cow's milk and cannot be used as the latter,s substitute.

2.Allergy to eggs is ususlly observed in young children and like cow's milk allergy fades with time The main allergens are the egg -white proteins ovomucoid ovalbumin and ovotransferrin to that hens anda also cause allergy

3Seafood allergy is more common in adult tham children and is more prevalent in countries with a high consumption of fish and shellfish The major in fish are flesh-proteins called pravalbumins, Which are similar in all all kind of the coooked  and not raw fish.

4. Certain fruits and vegetables are also capale of causing allergic reactions though very mild and often limited to the mouth (oral-allergy syndrome) The commonly allergic fruits and vegetables are apples bananas, tomatoes soyabean , peas, and beans Many of thes allergens are destoyed by cooking and are thus safe in allergyic individuals

5. peanuts are one of the  most allergenic food and frequently cause very severe reactions including death This alergy is established in childhood in and is usually maintained throughat life Traces of peanuts found in processed oils or in utensils used for serving foods can be enough  in some individuals to cause an allergic reaction.

6.Tree nuts such as walnuts almonds, cashewnuts, hazelnuts and pistachios can cause very severe allergic symptoms, which can occasionally be fatal Roasting or cooking cannot destroy the allergens

7.Certain cereals like wheat rice barley rye oats and maize are also associated with allergy The more we eat these cereals associated with allergy. The more we eat these cereals the more likely we are to suffer an allergy Seed storage proteins such as wheat gluten and other proteins present in grain to protect it frome bacteria and fungi have been found to be major allergens

8.Food additives and preservatives like sulfites tartrazine, monosodium glutamate are also responsible for causing food allergy.

Drug Allergy

Almost everyone in his life time has undergone certain unpleasant effects due to medicines Some may develop drowiness,  others develop stomach disorders like diarrhoes or consitipation or hyperacidity and a few develop headache giddiness, etc These dre usually the know side -effects due to overdose or drug -interactions. Drug allergy usually refers to serious adverse  effects in a person, which may not have occurred while taking the same medicine earlier. The mechanism of these effects are due to production of  Immunoglobulin E awsin the case of oher allergies. Usually people with drug allergies have a family history of allerges and may be also suffering form dust allergy or food allergy.

1.penicilline group  and Cephalosporins

2.Indulin

3.Vaccines like DPT, Influenza (HIB) Tetanus, MMR, Chickenpox

4. Sulfonamides (Suifa drugs)

5. Intravenous contrast  dyes used in tests like CT Scan MRI IVP, MRI, ivp,etc.

6.Aspirin and other painkillers

7.Local and general anaesthesia

Insect Allergy

Usually insect Bites and stings cause mild and temporary pain and swelling at the site of the bites In sensitised individuals, allergic reaction may result in more severe local reaction as well as generlised symptoms ranging frome mild to fatal responses. The insects which usually cause allergic symptoms are as follows :

1. Bes -hone7y bees bumble bees

2.Wasps hornest, yellowjackets

3.Fire ants

4.Mosquitoes

The risk of insect bites increases in summer and rainy weather and can occur with outdoor exposure Incidence is more in ussanitery areas, forests and grassy areas and near the water bodies Loose fitting clothes may entrap insects, Insects are attracted to bright colours and floral patterns and to perfumes lotions scented soaps and hair preparations.

Skin allergy

Several soaps, detergents perfumes ,cosmetics dyes and items of daily use produce allergic reactions at site of contact This is referred to as skin allergy. effects are more common in thinner sites like eyelids earlobes and genital sites and less in palms of hands soles of feet.

The following are the allergens and the sources where they are found;-

1.Plants - poison ivy poison oak chry-santhemum,tulips,  rosewood pines.

2.Nickel  - Jewellery, watches jean studs bra clip.

3.Rubber/Latex - Gloves condoms clothing shoes tyres.

4. Epoxy resins - Sticking plaster adhesives, sealants collodion.

5. Wool alcohol (Lanolin)- Adhesives, paints surface coatings.

6. paraphenylendiamine- Hair dye shampoo conditioners.

7. Balsam of peru - perfumes citrus fruits

8. Neomycin - Ointment cream eye drops,lotions.

9. Furazoloine - Furacin ointment.

10. Potassium dichromate - Cement,industrial chemical

11. Thiomerasol - Preservatives in cosmetics, nose drops and ear drops

                          

Allergy Due to other substances:

Solar Allergy:

Many people are allergic to sunlight and develop skin disease (dermatitis) within minutes of exposure to sunlight The ultraviolet rays of the sun act the trigger for allergic changes on the skin Sometimes sunscreening agents used in cosmetics such as moisturisers lip and hair preparations and foundation make -up accelerate solar allergy.

Allergy Towards pets:

Many people with a history of dust allergy or food allergy who keep pets at home have been observed to have allergic symptoms due to the pets Dogs and cats are such faithful and lovable animals that millions of people keep themas pets at home majority of people play with them or bathe themor even make them stay in their bedroom without facing any problems But certain individuals immmediately start sneezing and coughing when they enter the room where the animals are located Such people are known to suffer from pet allergy The allergens in dogs are the dead skin flakes or epithelial scales and in the cat the sebum frome the  sebaceous glands near the base of the tail. Hair or feathers from cattle house sheep, goat duck and other birds also have an allergic effect Urine salive and bacteria of these animals as we ll as rats  and mice can also cause allergy.