Allergology is a branch of internal medicine dedicated to the diseases caused by excessive (i.e. allergic) reaction of the human immune system. Allergologists are physicians who have received special training in allergology and who diagnose, observe and treat allergy-related diseases. Quite often pediatricians or pulmonologists take allergology as an additional specialty.
Allergology is closely related to the concepts of allergen and allergic reaction. Allergy develops when the reactivity of the human immune system changes and the body becomes overly sensitive to substances that are usually totally harmless. Allergy may manifest in different ways, such as asthma, rhinitis, conjunctivitis, atopic dermatitis, hives (urticaria) or anaphylaxis. Sensitization (which means “becoming sensitive”) to an allergen occurs when the content of IgE antibodies, specific to a certain substance, increases in the organism.
Allergen is an exogenous (i.e. originating from outside the body) organic or anorganic substance that, after coming into contact with the immune cells, induces a release of inflammatory signals from these cells. The release of histamine and other signaling substances starts a defence reaction, leading to the symptoms of inflammation (swelling, erythema, fever, itching and rashes). Sometimes the allergic reaction can be very strong and affect the airways, causing swelling in the throat and breathing difficulties. This kind of very strong and life-threatening allergic reaction, also called anaphylactic reaction, is characterized by circulatory disturbances, breathing difficulties, and loss of consciousness. In case of an anaphylactic reaction, adrenaline needs to be administered during the first couple of minutes, otherwise the condition may become life-threatening.
Allergic diseases can sometimes be diagnosed on the basis of medical examination and the information collected from the patient. Allergic reaction is often characterized by symptoms such as skin rash, rhinitis, red eyes, or specific auscultatory finding (wheezing sounds during exhalation). However, often it is necessary to do allergy tests as well to determine allergens that should be avoided. The first step in the treatment of an allergy is to avoid contact with the substance(s) that cause allergy. Allergy tests can be divided into two main groups: measurement of IgE antibodies from blood, and epicutaneous tests or patch allergy tests. By blood analysis, the concentrations of IgE antibodies against different inhalable allergens (e.g. different pollens) and food allergens (e.g. cereals) can be measured. However, blood testing has its disadvantage as the detection of antibodies does not necessarily mean that the person is allergic and has symptoms. Epicutaneous tests, also called patch allergy tests, are the most important method for diagnosing allergic contact dermatitis. This test is performed by attaching the allergen of interest onto the skin by means of an adhesive plaster. In persons sensitive (allergic) to this allergen, an inflammatory reaction develops in the place of contact. The disadvantages of these tests include higher price and complicated procedure. However, epicutaneous tests enable to study the real impact of an allergen on the organism. An inflammatory reaction develops only in people who are sensitized (that is, allergic) to the tested allergen.
Treatment of allergic diseases is usually symptomatic or, in other words, directed at alleviating the symptoms of the patient. The main medications used for alleviating the symptoms are antihistaminergic drugs or derivatives of corticosteroid hormones (hormones of the adrenal glands). Older antihistaminergic drugs have a calming and sedative side effect, which is why they are sometimes as sleeping pills. Patients with allergies prefer newer (second generation) antihistaminergic drugs that do not make you sluggish and tired. Corticosteroid hormones are administered locally, in the form of nasal sprays, or in the form of inhalable asthma medicines or skin creams. In case of stronger and systemic reactions, oral or injectable drugs can be used.
In some rare cases, specific immunotherapy is indicated, whereby the excessive allergic reaction of the organism to a specific allergen is neutralized. During this treatment, the allergen or the combination of allergens causing symptoms is injected to the patient in small, but gradually increasing doses with the purpose of making the patient less sensitive to the same allergen(s). Allergen-specific immunotherapy can be used in patients: 1) who have been diagnosed by an allergologist-immunologist or a pediatric allergologist with anaphylaxis, allergic rhinitis, rhinoconjunctivitis and/or asthma caused by IgE-mediated allergy; 2) who do not have contraindications for allergen-specific therapy; 3) who have followed the treatment regimen. Allergen-specific immunotherapy can only be performed by a specialist with proper training. Immunotherapy is discontinued when after two years from the commencement of the therapy, according to the attending physician’s judgement, no significant improvement has been attained in terms of the frequency and severity of symptoms, number of relapses, use of medications, and change in life quality, compared to the pre-treatment period.
Allergologist’s consultation12 clinics
An allergologist is a specialized physician in the field of internal medicine, who focuses on allergies and hypersensitivity reactions. The most common problems why people seek the help of an allergologist include immune reactions caused by respiratory, skin and gastrointestinal allergens. These reactions can manifest as rhinitis, cough, rashes or abnormal bowel function, for example. During the first appointment, the allergologist examines the patient, prescribes necessary allergy tests and, if possible, plans treatment.