Symptomatic drug treatment with antihistamines or corticosteroids may be prescribed to calm the symptoms of the allergy. Elimination of exposure to the allergen in question is necessary to avoid a recurrence of the allergic symptoms. Desensitization makes the person tolerant of the allergen.
Antihistamines
The so-called second-generation antihistamines (cetirizine, levocetirizine, fexofenadine, loratadine, desloratadine, mizolastine, and ebastine) are the most widely used because they have few side effects (drowsiness and increased appetite). They are active in the symptoms of rhinitis, conjunctivitis, and itching, but they have no effect on asthma.
They are available in tablet form and some in eye drops and nasal solutions.
Corticosteroids
Their anti-inflammatory action calms allergy symptoms.
Apart from their use by injection in emergency situations, corticosteroids are mainly used by the nasal route or by inhalation.
Adrenaline by injection
This is the emergency treatment for anaphylactic shock.

The choice of treatment according to the manifestations of the allergy
Once the allergy has been diagnosed, the doctor prescribes a treatment that depends on the type of allergy:
- allergic rhinitis is often improved, depending on its intensity, by antihistamines and local treatments with nasal solutions (corticoids or antihistamines) associated with nose washes ;
- asthma is treated to calm the acute attack. If necessary, daily treatment with inhaled corticosteroids may be prescribed;
- Allergic conjunctivitis is relieved by antihistamines and the use of antihistamine eye drops;
- Hives (with or without edema) are not always synonymous with allergy. When the allergy is present, apart from treating the cause, it is necessary to use antihistamines or even corticoids;
- Atopic eczema is treated by permanent hydration of the skin, by emollient substances, and the application of corticoids, if necessary;
- Anaphylactic shock is a particular allergic manifestation. It is a medical emergency treated by intramuscular injection of adrenaline, often in a self-injectable form.
- Medical treatment usually restores quality of life by improving or eliminating the symptoms of allergy.
TREATMENT OF THE CAUSE OF ALLERGIES
The most effective allergy treatment is the elimination of exposure to the allergens responsible for the symptoms. Desensitization may also be offered.
Eliminate exposure to allergens if possible
Avoiding the allergen is possible in some cases.
This is often true when the allergen is food (top allergen) or medication or when it is a pet hair allergy.
It is more difficult in the case of dust mite allergy.
Avoidance is impossible in the case of a pneumallergen (pollen, grass, dust mites…)
Eliminating exposure to the allergen is also difficult when the allergen is poorly identified, difficult to avoid or when there are multiple allergens.
Allergy: When can desensitization be used?
When one or two allergens are responsible for troublesome allergic symptoms, the allergist may suggest desensitization to the patient.
Desensitization (or specific immunotherapy) consists of administering, over a long period of time (several years), allergen extracts in progressive doses, in order to stimulate the immune system and make the person tolerant to the substance.
This is done by subcutaneous injection under medical supervision or by sublingual intake, depending on the results of the allergological assessment.
The allergens for which this desensitization is most effective are dust mites, certain pollens, and Hymenoptera venom (wasps, etc.).
Side effects (triggering of rhinitis, asthma attacks, drop in blood pressure, etc.) occurring after the product has been administered may be warning signs and force the treatment to be interrupted.
The beneficial effects which you can find more here are often perceived after a few months and persist after the treatment is stopped.