Allergy medicine

Allergy specialists deal with a wide range of allergic diseases and the main ones are:

• Asthma
• Allergic rhinitis and hay fever
• Allergic conjunctivitis
• Rhinosinusitis and nasal polyps
• Eczema
• Anaphylaxis
• Urticaria and angioedema
• Food allergy
• Oral allergy syndromes
• Allergic gastrointestinal disease
• Food intolerance
• Drug allergy
• Latex allergy
• Venom allergy
• Occupational allergy

Allergic diseases affect more than a quarter of the population and the symptoms range from mild and irritating to severe and life-threatening. The allergist's role is to identify or exclude allergy, and provide management including symptom-suppressing drug treatments, allergen avoidance, immunotherapy and self-management plans for acute severe reactions.

Allergic symptoms result from a damaging immune response by the body to an otherwise harmless substance, typically a protein, to which it has become hypersensitive. Allergic disease is wide ranging and may be, especially in children, progressive if not effectively managed. Multiple disorders and multiple allergies commonly co-exist in a single individual. For example, a patient may present with asthma, rhinitis, eczema, food allergy and anaphylaxis. A proportion of patients suffer severe or life-threatening disease, or disease that impairs their schooling or ability to work.

Good allergy care requires accurate allergy diagnosis to identify allergens and enable their exclusion. The most important tool for the allergist is the detailed allergy-focused history. Allergy skin-prick and/or specific IgE blood tests are frequently required. However, a draw-back is the existence of both false negative as well as false positive responses on both skin prick and specific IgE blood tests. Allergy specialists therefore believe that food allergy tests in particular should not be undertaken by practitioners without allergy training. It is poor practice to allow specific IgE blood tests to be made directly available to patients without expert interpretation and even worse if patients have alternative allergy tests possessing no scientific validity.  

Management includes avoidance advice, the training in self-use of rescue medication in case of anaphylaxis due to inadvertent allergen exposure, and the use of safe long term medications to control chronic conditions. If patients are educated in the self-care of chronic conditions such as asthma, rhinitis or eczema in most cases the condition will be effectively controlled.

In the case of food or drug allergy or anaphylaxis, it is reasonable to expect that avoidance will result in disease prevention. Patients may be trained in avoidance of triggers to prevent or reduce disease (anaphylaxis, asthma, eczema) the self-administration of drugs to deal with acute attacks, and the use of prophylactic treatment for predictable allergen exposure.

A major aim of the allergist is to avoid the development of chronic illness. Allergen immunotherapy treatment (desensitization) treatment may be considered in occasional cases. It is especially valuable when a single allergen is responsible for severe symptoms; anaphylaxis due to wasp venom allergy and severe hay fever due to grass pollen allergy are two examples. The treatment involves giving increasing tiny doses of the allergen which may be injection (subcutaneous immunotherapy), or drops placed under the tongue (oral immunotherapy).

The main risk of subcutaneous immunotherapy is that although the injections occasionally cause mild reactions that could cause a severe allergic reaction. Although this form of treatment is nowadays regarded as safe, such treatments should only be given in hospital clinics and a wait of one hour after each injection is recommended.

As far as oral immunotherapy is concerned, only minor side effects such as mouth itch or slight swelling have been reported. Neither severe reactions nor anaphylaxis have occurred. Even so, it is recommended that the first dose of an oral immunotherapy treatment course should be given in a specialist clinic, although the treatment can then be safely continued at home.