The therapy against an allergy depends on its strength and severity. The range extends from simple ointments to the administration of life-saving emergency drugs such as adrenaline.
Specific immunotherapy – modes of action and implementation Therapeutic vaccines are well advanced in the treatment of some allergies (mediated by the antibody IgE). The purpose is to suppress or modify already expired immune responses to the allergen. The theory behind hyposensitization is to correct the further immune response mediated by the IgE, in which the further cells are probably transferred into a state in which they are no longer activatable, e.g. due to lack of energy or regulation, and thus cannot trigger further IgE production.
In hyposensitization for the therapy of allergies, the tolerability should be increased by repeated administration of the relevant allergen. This therapy method is mainly used in the therapy of pollen and house dust mite allergies, as well as allergies to toxins from bees and wasps. Since immunotherapy is not only time-consuming (monthly for 3-5 years) but also expensive, the benefits and risks (anaphylactic reaction up to shock) of treatment should be well balanced and only be used in patients with severe symptoms.
Further therapeutic principles
1) Antihistamines The messenger substance histamine is primarily responsible for allergic reactions and can trigger effects at four different receptors (H-receptors). An important point of attack for the drugs is above all the H1-receptor, through which allergic reactions are mediated. These reactions include itching and pain, but also narrowing of the arteries and bronchi in the lungs, which causes breathing problems.
Furthermore, the H1-mediated reaction increases the permeability of vessels. In this context, a blocked nose, rhinitis or swelling of the affected region may occur. The antihistamines bind to the receptor and thus prevent the messenger substance from attaching itself and triggering the described reaction.
The 1st generation drugs of this group, for example diphenhydramine, clemastine or dimetinden, not only have an anti-allergic effect but also cause severe fatigue, which severely limits the ability to perform and work. In addition, other strong side effects, such as cardiac arrhythmia or seizures, occur. In contrast to the first generation, second and third generation antihistamines (cetirizine, desloratadine, fexofenadine) do not pass the blood–brain barrier as well, which means that fatigue is less pronounced when taking these drugs.
The effect of these drugs unfolds mainly in allergic hives, rhinitis and conjunctivitis, caused by allergen exposure. For example, the antihistamines reduce itching and increased secretion production in the nose. Besides being taken in tablet form, the drugs are also available for use as eye drops or nasal sprays.
These drugs are part of the basic therapy of certain allergies. 2) Glucocorticoids Glucocorticoids are used in the therapy of allergies to suppress inflammatory processes and their spread. This effect is particularly useful in cases of inflammation of the skin, allergic nasal inflammation and allergic asthma. Side effects should be taken into account, especially with long-term use. In addition to glucocorticoids, there is the drug montelukast, which inhibits specific inflammatory cells (leukotrienes) and can thus be used in the treatment of (stress-induced) asthma.