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An allergist, also known as an immunologist, is a specialist who diagnoses and manages patients who are diagnosed with allergic conditions and asthma that is triggered by allergens.
In order to qualify as an allergist, a doctor needs to take part in a medical undergraduate degree which takes 5-6 years to complete. This is then followed by another 1-2 years completing an internship phase where the newly qualified doctor is exposed to the various medical and surgical disciplines.
The doctor is now able to specialise and needs to complete a 4 year residency programme in internal medicine where they will qualify as a physician. The specialist will then attend a 2 year fellowship programme in allergy/immunology to become a qualified allergist.
Causes of allergies
An allergist will need to have extensive knowledge of the following causes of allergies so that they know what needs to be tested for when consulting with a patient.
- Foods - peanuts, tree nuts, gluten, shell-fish, egg-whites, milk-proteins and oil-proteins in seeds.
- Medications - penicillin, hypertensive medications such as ACE-inhibitors and calcium channel blockers, Aspirin, certain anti-inflammatory medications and sulphur containing drugs.
- Latex - found in gloves used by healthcare workers and condoms.
- Hygiene hypothesis - the theory that being exposed to infectious agents decreases an individual's risk to be diagnosed with an allergic condition. This is seen in families with many children versus those with one or two, where the latter children will experience allergic conditions and the former won't.
- Genetics - parents who are allergic will have a greater chance of having children with allergies, and these allergies will be more severe. There's a 70% chance that identical twins will have the same allergy, if they are affected, and a 40% chance in non-identical twins.
- Stressors - chronic stress can aggravate and exacerbate allergic conditions.
- Toxins interacting with proteins - allergic reactions occur when coming into contact with plants such as poison ivy and poison oak that contain the protein-like compound urushiol.
Diagnostic investigations used by Allergists
This method is used to determine if a specific substance causes an allergic reaction on the skin. It is performed by applying adhesive patches, which contain skin sensitizers or common allergic chemicals, to the back. The skin is then examined for any reactions at 48 hours and then again 2-3 days later. Patch testing is used to test for delayed reactions.
Skin prick testing
A series of tiny pricks or punctures are made into the patient's skin using a small plastic or metal device. A small amount of the suspected allergen is then introduced to the open area of the skin which is then marked with a pen or dye. Another method of introducing an allergen is by injecting it just under the skin (intradermally) with a needle and syringe. The most common areas for performing skin prick testing include the back and the inside of the forearm.
Inflammation of the area will usually occur within 30 minutes if the patient is allergic to the substance, and the reaction will vary from a slight redness to that similar to a mosquito bite. The allergist will then interpret the results and manage the patient appropriately.
This is usually done on patients such as babies and young children where patch and skin prick testing is very invasive and painful. Blood tests check for the reaction to specific components of the blood (IgE) to a broad variety of allergens.
Blood tests aren't as specific as the other tests but they do indicate if an allergy is present and which group of allergens to be wary of.