Allergies
What are the different types of allergies? Information on the causes, symptoms, and treatments of this condition.
Symptoms and Causes
Allergies occur when the body triggers an immune response to a harmless substance (allergen) because it perceives it as harmful.
Depending on the allergen that triggers the reaction, allergies are classified into five major groups:
- Allergic contact dermatitis: This occurs when the skin comes into contact with the triggering substance. Some of the most notable examples include allergies to water (aquagenic urticaria), cold (cold-induced urticaria), sweat (cholinergic urticaria), or certain plants.
- Food allergy: This happens when consuming certain foods. The most common ones include allergies to eggs, fish, milk, nuts, or shellfish.
- Rhinoconjunctivitis or respiratory allergy: One of the most common chronic diseases in children. It is triggered when the allergen is inhaled or comes into contact with the eyes. The most characteristic forms include allergies to dust, mold, pet dander, or hay fever (pollen allergy).
- Drug allergy: Caused by taking a medication that the body perceives as harmful. The most notable examples are allergies to penicillin, amoxicillin, or certain chemotherapy drugs.
- Insect allergy: Triggered by substances entering the body through an insect sting. Common examples include allergies to mosquito bites, wasps, spiders, or bees.
In most cases, the symptoms are bothersome but mild and can be controlled by avoiding exposure to the allergen and using appropriate treatment. However, caution is necessary because some allergic reactions can become severe and life-threatening. In such cases, urgent medical attention is required to administer a dose of adrenaline.
Symptoms
Symptoms vary depending on the type of allergy. The most significant ones include:
- Allergic contact dermatitis: Skin redness, peeling, blisters, or vesicular lesions.
- Food allergy: Usually causes hives, itching, or swelling. In less common cases, it can lead to abdominal pain or vomiting.
- Rhinoconjunctivitis or respiratory allergy: Coughing, nasal congestion, red eyes, tearing, wheezing when breathing, or shortness of breath.
- Drug allergy: Skin rash, itching, or burning sensation.
- Insect allergy: Swelling at the sting site, hives, or angioedema (swelling under the skin).
When an allergic reaction is severe, it can cause anaphylaxis or anaphylactic shock, which immediately affects the entire body and manifests with itching, redness, rapid heartbeat, difficulty breathing, or loss of consciousness.
Causes
Allergies are caused by an immune system malfunction, which responds to a normally harmless substance as if it were a dangerous agent. As a result, it generates antibodies (such as histamine), which are released upon contact with the substance.
Risk Factors
Some factors that increase the risk of developing allergies include:
- Family history.
- Having asthma.
- Being a child, as allergies are more common at this stage of life.
Complications
Allergies can lead to other conditions such as asthma, sinusitis, or lung infections. They can also cause anaphylactic shock, which is life-threatening.
Prevention
The only way to prevent allergies is to avoid contact with the triggering substance.
Which Doctor Treats Allergies?
Allergies are diagnosed and treated by specialists in allergology. In cases of anaphylaxis, emergency physicians may also intervene.
Diagnosis
After taking a medical history and analyzing the symptoms reported by the patient, allergies are diagnosed through the following tests:
- Skin prick test: Drops of different allergens are applied to the arm, and the skin's reaction is observed after about fifteen to twenty minutes.
- Provocation test: Used in cases of food or drug allergies. The patient is monitored after ingesting the suspected allergen.
- Blood test: Detects and quantifies the specific antibodies (immunoglobulin E) that trigger allergies.
Treatment
Allergy treatment generally consists of:
- Recommendations to avoid exposure to the allergen.
- Medication: Antihistamines yield excellent results, along with topical or inhaled corticosteroids.
- Allergy vaccine: Immunotherapy can prevent allergic reactions even when exposed to the allergen. This involves injecting small doses of the allergen multiple times over three to five years. In some cases, the vaccine is in the form of a tablet placed under the tongue until it completely dissolves.
- Adrenaline injection: Administered intramuscularly to treat anaphylaxis
