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Allergy Investigations

Allergy InvestigationsEveryone is individually unique. Allergy tests provide concrete specific information about what you are and are not allergic to. You or your attending physician need not to guess inaccurately any longer. Be certain. No more guessing!

Skin Testing for allergy

There are various methods for allergy testing. The simplest of which are skin prick testing or intra-dermal testing. Although slightly cheaper, these tests cannot be carried out on patients who are on many common medications, may not be as accurate unless done properly by highly trained personnel, may cause minor pain and discomfort with multiple needles being utilized and most importantly although rare, carry an increased risk of severe side effects such as anaphylaxis. The number of substances being tested are also very limited. This is still a good but basic testing modality.

In-Vitro Testing

Assessing the level of allergen- specific IgE in a patient's serum in conjunction with a clinical evaluation based on patient history and subsequent testing can help a doctor confirm a diagnosis of atopic allergy and assist in the treatment of the patient.

Treatment Options

  • Once a diagnosis of atopic allergy to one or more specific substances is made, doctors have several treatment options to consider: Have patients avoid subsequent exposure to identified allergen(s)

  • Employ a course of state of the art pharmacotherapy to treat allergic symptoms

Allergic inflammation.

Allergic rhinitis occurs in "atopic" youngsters usually with raised blood levels of IgE antibodies to the common inhalant allergens such as house dust mites, tree and grass pollen, animal dander, cockroaches and mould spores. Occasionally foods such as milk and food additives can cause worsening symptoms. Children are sensitised in early life but may only manifest their allergy symptoms later in life. Perennial allergic rhinitis usually manifests before the age of 10 years, while seasonal allergic rhinitis occurs more commonly in teenagers and young adult males. Primary sensitisation results in the production of specific IgE antibodies, which later cross-link with allergens on mast cells in the nasal membranes releasing histamine and the allergy cascade. If the condition becomes more entrenched as occurs in chronic perennial rhinitis, then other inflammatory mediators and immune cells become involved.

The allergy reaction in the nose involves a complex interaction between various inhalant allergens and immune cells. An allergen will link to specific IgE antibodies on mast cells near the nasal surface, resulting in histamine release. This is termed the Immediate Allergic Reaction. Other chemicals released by Mast cells include tryptase and prostaglandin. Histamine has a direct effect on nasal blood vessels causing swelling and nasal obstruction. It also has a reflex effect via sensory nerves causing sneezing, itching and further mucus production. This triggers a sequence of events with sneezing followed by watery nasal discharge and finally nasal blockage.

Subsequent nasal symptoms that develop between 3 and 12 hours after the initial allergen exposure are due to the Late Phase Reaction. Further immune  mediator production occurs in the already inflamed nasal membranes and blood cells (eosinophils and basophils) infiltrate causing  progressive nasal blockage and swelling.

Nasal hypersensitivity occurs when non-allergenic irritants such as dusts, perfume, tobacco smoke, ozone, sulphur dioxide, nitrogen dioxide, cold air and other environmental pollutants result in increased nasal membrane leakiness, increased nerve excitability, white blood cell infiltrates and more mast cells in the superficial nasal membranes. These factors lead to an increased nasal irritability to low doses of allergens. Some older blood pressure medications such as reserpine, methyldopa, ACE inhibitors and alpha blockers as well as hormone replacement therapy (HRT) may in addition cause nasal obstruction. The last trimester of pregnancy is associated with worsening of nasal symptoms due to hormonal factors. While aspirin sensitive individuals will often develop rhinitis, sinusitis and nasal polyps after aspirin re-exposure.

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