An allergy is an overreaction of the immune system to the body’s exposure to a number of substances. The clinical picture can be caused by food, medicines, insects and animals.
The 8th of July, World Allergy Day, highlights the importance of diagnosis and treatment for the control and prevention of allergic crises.
Learn about the main causes of allergies and learn how to prevent them.
Respiratory allergies and rhinitis
Respiratory allergies can be caused by a variety of factors, including dust mites, pet dander, mold and flower pollen.
“Usually, the animal’s fur is not what causes the allergy. They are proteins from the sweat, salivary and sebaceous glands that stick to the hair and, when the person breathes, they react to these substances”, explains researcher Luisa Karla de Paula Arruda, coordinator of the Scientific Department of Allergens of the Brazilian Association of Allergy and Immunology (ASBAI ).
To minimize the impact of respiratory allergies, it is necessary to adopt strategies to control the environment, such as placing waterproof covers on mattresses, avoiding dust mites, or restricting the movement of animals in the internal environments of the house – such as bedrooms.
According to the researcher from the Brazilian Association of Allergy and Immunology, rhinitis is one of the most common allergic diseases. “We estimate that in Brazil around 30% of the population has rhinitis. Most, around 85% of cases, are of allergic origin. Some patients may have this condition due to viral infections and other causes”, says Luisa.
In general, allergic rhinitis is characterized by chronic and recurrent cases, mainly by exposure to mites present in dust, pollen, fungi, urine and saliva of animals such as dogs and cats.
The most common symptoms are swelling of the mucosa with nasal obstruction, runny nose, repeated sneezing and itchy nose, throat and eyes. Diagnosis can be made from investigating the patient’s history, in addition to skin tests and blood tests.
According to specialists, the treatment is diversified and includes environmental control, use of medication and immunotherapy. Rhinitis can be controlled by preventing contact with the causative agents.
Milk and seafood are among the causes of food allergy
Allergic reactions can also be caused by substances in food . Cow’s milk, egg, wheat, soy, peanuts, shrimp and other seafood, as well as nuts and chestnuts are some of the main allergic agents for some people.
“Excluding what causes the reaction is one of the ways to prevent and treat it. For example, a person who had an allergic reaction to shrimp, if we prove that this was the cause, the exclusion diet will solve the problem”, explains Luisa.
Although insect bites may not pose any health risk , some people may experience an allergic reaction shortly after contact with insects. Bees, wasps, hornets and ants can release harmful substances, which may indicate the need for medical attention.
A bee sting, for example, may have local or systemic manifestations. The simplest include acute local pain, which tends to disappear spontaneously in a few minutes, leaving redness, itching and swelling.
The systemic picture presents itself as manifestations of a severe allergic reaction, with symptoms of rapid onset, 2 to 3 minutes after the bite. In addition to local reactions, symptoms such as headache, vertigo and chills, agitation, feeling of tightness in the chest, among other symptoms, may be present. In that case, seeking medical attention should be done immediately.
“For cases that we cannot avoid, such as insect bites , we have treatment with immunotherapy, which are allergy vaccines. Today, there are subcutaneous and sublingual vaccines. The idea is to desensitize the person to that component”, says Luisa.
Attention to medications
Self-medication, which consists of using medication without a prescription or guidance from a doctor or health professional, poses health risks, including the possibility of an allergic reaction.
Medications such as anti-inflammatories, analgesics (aspirin, dipyrone, ibuprofen, diclofenac) and antibiotics (mainly pelicillins) can cause reactions.
“Through the tests, we advise the patient on what he can or cannot take. Identifying the groups to which the drugs that cause the reactions belong is fundamental”, says Luisa.
Manifestations on the skin
In general, allergies can manifest skin symptoms such as hives, swelling and redness. However, skin allergies are also part of a specific group of these reactions.
“An example is atopic dermatitis, a skin allergy that impacts quality of life because it causes intense itching and can lead to the formation of lesions. It can be caused either by mites or food or by local bacterial infections,” says Luisa.
Another type of skin allergy is contact dermatitis , which can be caused by metals and chemicals in general, according to the specialist.
“It is common, for example, to be allergic to jewelry in the area in contact with the skin. It is usually caused by metals such as nickel and chromate. Several other chemical substances can provoke reactions, such as makeup, personal care products, cosmetics, fabrics and rubber”.
How to prevent the development of allergy
According to professor at the University of São Paulo (USP) Fábio Castro, prevention includes the adoption of healthy habits from childhood, such as breastfeeding with breast milk for babies, in addition to a balanced diet, physical activity and contact with nature throughout of life.
In general, the discovery happens after a first event of allergic reaction. Experts recommend that people seek medical care at the first manifestations so that the causes can be investigated.
According to Fábio, the diagnosis is made from the investigation of the patient’s history, a stage in which his most recent activities are determined, such as places he frequented and food consumed before the reaction.
How to control allergy and increase quality of life
Treatment depends on the causative agent of the allergic reaction and can be carried out using different strategies, such as environmental control, immunotherapy ( vaccines ) and medication.
Specialists avoid using the term “cure”, but affirm that it is possible to achieve allergy control. “Today we can offer symptom control so that the patient can lead a normal life, without the allergy getting in the way of activities”, says Luisa.
According to Fábio, immunotherapy consists of the use of vaccines produced with the controlled use of different substances that cause allergic reactions. The purpose of the method is to desensitize the patient to the type of material that causes the allergy, that is, to make the body get used to the substance.