Alergy Unit

Allergic symptoms differ according to the affected system. The most frequent include:

Skin allergies

These affect the skin and may cause pruritus (itching), erythema (redness), urticaria, angioedema and eczema…

Digestive allergies

These affect the gastrointestinal tract and may present with itching of the oral cavity, abdominal pain, nausea, vomiting and diarrhoea.

Respiratory allergies

These may affect any part of the respiratory tract, from the nose to the bronchi. Symptoms include sneezing, rhinorrhoea (runny nose), nasal congestion, wheezing, shortness of breath and asthma.

Cardiovascular allergies

These may cause hypotension, dizziness, instability and loss of consciousness.

As mentioned above, allergic reactions are often more severe during childhood and may lessen over time. However, allergies can also develop in adulthood, and allergic patients frequently present with more than one allergy simultaneously. The most common complications include:

Asthma

A condition characterised by narrowing of the airways, leading to shortness of breath, breathing difficulty, chest tightness, wheezing and cough.

Anaphylaxis

A severe, life-threatening allergic reaction that requires immediate medical attention. It affects the entire body and progresses rapidly, causing breathing difficulty, intense itching, tachycardia, dizziness and loss of consciousness. In severe cases, it may lead to cardiovascular collapse and death.

Sinusitis

An inflammatory condition that may become chronic, characterised by inflammation of the paranasal sinuses—air-filled cavities located on either side of the nose that drain mucus into the nasal cavity. Common symptoms include cough, breathing difficulty, nasal congestion and fever.

At the Allergy Unit, diagnosis is carried out through a comprehensive clinical assessment, physical examination and complementary tests selected by the specialist allergist according to each case.

Skin allergy tests

Skin tests are considered the diagnostic method of choice in allergic patients. They are safe and simple to perform and involve introducing a small amount of allergen extract into the skin via a superficial prick. Results are read after 15–20 minutes, providing immediate information on sensitisation. These tests are performed using extracts of common aeroallergens (pollens, dust mites, fungi, animal dander and insects), as well as specific allergens such as foods.

Patch testing (epicutaneous tests)

Also known as patch tests, these are used to differentiate irritant dermatitis from allergic contact dermatitis. Patches containing potential allergens are applied to the upper back and left in place to observe skin reactions. Results are read at 48 and 96 hours.

Respiratory allergy tests

Spirometry is the test of choice for assessing respiratory function. This non-invasive test measures the volume and speed of exhaled air using a device called a spirometer. It is essential for the diagnosis, monitoring and prognosis of bronchial asthma.

Immunoglobulins and antibodies

This blood test evaluates total serum IgE levels and the activity of IgE antibodies. It is often indicated when allergic disease is suspected, as it provides valuable information for the allergist in a simple and accessible manner.

Diagnosis of urticaria and angioedema

The diagnosis of urticaria and angioedema requires a thorough assessment that includes a detailed clinical history to classify the condition correctly. Additional tests are often performed, particularly blood tests, analysis of secretions or stool samples, and skin biopsy in a significant number of cases. The aim is to clearly identify the cause of the allergic reaction, as its severity may be life-threatening in certain situations.

Some of the most frequent allergic conditions include the following:

Respiratory allergies

These are triggered by inhalation of allergens such as pollen, aerosols or dust. They typically cause allergic rhinitis and conjunctivitis (affecting the nose and eyes), as well as bronchial asthma and/or breathing difficulty.

Food allergies

Allergic reactions to food represent a significant public health issue, both due to their high prevalence and the potential severity of reactions, which in some cases may be life-threatening.

The foods most commonly responsible for allergic reactions in children are milk, egg and fish, whereas in adults, plant-based foods such as fruits and nuts are more frequently involved.

Urticaria and angioedema

Urticaria is an allergic reaction characterised by skin inflammation, intense itching and wheals that resolve over a variable period of time. Acute urticaria lasts less than six weeks, whereas chronic urticaria is defined by the presence of wheals daily or almost daily for more than six consecutive weeks.

Angioedema may be confused with urticaria, but they are not the same condition. Angioedema presents with tingling, pain and burning sensations in the skin and, unlike urticaria, affects deeper layers of the skin and is usually not itchy. It causes swelling of the lips, eyelids, cheeks, hands and feet, and may also involve the glottis, tongue or uvula. This constitutes a serious clinical situation requiring urgent medical attention.

Hymenoptera allergies (bees and wasps)

Stings from hymenoptera insects usually cause mild skin reactions in most people, which resolve shortly afterwards. However, in some individuals they may trigger severe allergic reactions that can be fatal.

Anisakis simplex allergy

This allergy is caused by an immune reaction to the parasite Anisakis simplex, which may be present in fish and cephalopods (such as octopus, cuttlefish or squid). Symptoms are highly variable and may range from digestive problems (nausea, vomiting, diarrhoea, abdominal pain) to anaphylactic shock. Skin manifestations such as angioedema and urticaria may also occur and can be life-threatening.

Latex allergy

Latex allergy is considered a particularly important medical condition due to the severity of the reactions it may cause, as well as its frequent association with food allergies.

Contact dermatitis

Contact dermatitis is a specific inflammatory skin reaction caused by direct contact with external agents, either irritants or allergens.

Atopic dermatitis and allergy

Atopic dermatitis is a chronic inflammatory skin disease characterised by eczema. It is estimated that approximately 80% of patients diagnosed with atopic dermatitis also develop allergic rhinoconjunctivitis and/or allergic bronchial asthma.

Avoidance of allergens

The cornerstone of allergy treatment is avoiding, as far as possible, contact with the substances or agents responsible for allergic reactions. To achieve this, it is essential to establish a precise diagnosis and identify the specific triggers involved.

Medications

Allergy medications aim to reduce the intensity and severity of symptoms and to modulate immune system activity in order to control the condition. These may include topical, oral, injectable or inhaled treatments.

Immunotherapy

Depending on each case—such as severe allergies, long-standing conditions, exposure to very common allergens, multiple allergies or poor response to medication—the allergist may recommend immunotherapy. This treatment involves the controlled, periodic administration of a vaccine containing clinically relevant allergens for the allergic patient. The goal is to reach an effective dose that controls symptoms triggered by exposure to the causative allergen. In doing so, immunotherapy may also help prevent or reduce serious complications such as bronchial asthma, angioedema or anaphylactic shock.

Emergency medication

Patients with a history of severe allergic reactions may require injectable medications designed to relieve severe symptoms and prevent rapid progression to life-threatening situations. These medications are usually provided in easy-to-use auto-injector pens, allowing the patient or anyone assisting them to administer treatment promptly and effectively.

The content of this page has been prepared by the Communication Department and the Medical Team of Grupo Pedro Jaén, in line with our editorial commitment to accuracy, scientific rigour and up-to-date medical information.