Allergy
Einstein Health Glossary
ICD 10 - T78. 4
What is an allergy?
An allergy is an exaggerated response of the immune system to a substance foreign to the body, known as an antigen.
Allergic reactions are classified based on the time elapsed between the contact of the sensitized organism with the antigen and the appearance of the allergic phenomenon.
Thus, while immediate hypersensitivity reactions appear within minutes, delayed hypersensitivity reactions only develop after several hours.
Although this time-based classification remains valid, it is now understood that more significant differences exist between the two types.
Causes
An allergic reaction results from a massive release of chemical substances into the bloodstream, produced by the body itself. One of these substances is histamine, which causes symptoms such as itching, swelling, skin redness, and sneezing.
Allergic reactions can be triggered by various factors, including:
- foods
- medications
- common allergens, such as pollen, animal dander, latex, and insect stings
- Environmental factors, such as heat, cold, sunlight, water, pressure on the skin, emotional stress, and physical exercise
Other medical conditions, such as low immunity and autoimmune diseases
Symptoms
Allergic reactions can cause a wide range of symptoms, including:
- General discomfort
- palpitations
- tingling sensation
- itching and redness of the skin
- pulsing sensation in the ears
- cough
- snnezing
- red, swollen patches on the skin, known as hives (urticaria)
- localized swelling, including in the mouth, tongue, or throughout the body
- difficulty swallowing
- difficulty breathing and wheezing in the chest
Diagnosis
The diagnosis of allergy is primarily clinical, meaning it is based on the patient’s medical history and physical examination.
This diagnosis can be supported by skin allergy tests and laboratory tests. Skin tests can be performed in the specialist’s office and are usually sufficient to confirm the diagnosis.
If these tests do not provide the necessary information, the specialist may request additional laboratory tests.
Treatment
The treatment of allergic reactions should focus on managing symptoms, removing distancing the patient from the allergen, and, in selected cases, oral tolerance induction (in food allergy) or specific immunotherapy.
Treatment can be divided into acute phase and chronic phase approaches.
Symptomatic treatment
Symptom management is carried out using corticosteroids and antihistamines. In cases of respiratory allergies, inhalation therapy may be necessary.
Symptomatic medications are prescribed according to each individual’s needs. It is also essential to the person from the allergen causing the reaction.
In cases of anaphylaxis, the first-line treatment is always intramuscular adrenaline.
Specific treatment
The curative approach is Specific Immunotherapy, also known as Desensitization.
Desensitization is a treatment method in which the patient receives minimal and progressively increasing doses of the allergen.
Specific Immunotherapy is the only treatment capable of modifying the natural course of the disease.