Allergies: Different Types of Allergy and Their Symptoms

Allergies take many forms and affect a great many people. Insect stings, pollen, food or house dust – the list of allergens is a long one. Here you will find a brief overview of the most common allergies and their symptoms, together with a list of the best clinics in Switzerland, where you can be diagnosed and treated for allergies.

01 About allergies

An allergy occurs when the body overreacts to an allergen or “trigger” that is usually harmless to most people. Examples of allergies include:

• allergic rhinitis
• asthma
• eczema
• hives (urticaria)
• food allergy.

Allergy symptoms range from mild to severe. The most severe type of allergic reaction is anaphylaxis, which can be fatal without an immediate injection of adrenaline. For mild allergies, effective treatments are available, both for the allergy itself and for its symptoms.

02 Allergy symptoms

Symptoms depend on the allergy but may include:

• swelling of the lips, face or eyes
• sneezing
• a runny nose
• red, watery and itchy eyes
• wheezing or a persistent cough
• breathing difficulties
• swelling of the tongue and tightness in the throat
• headache
• skin rash
• abdominal pain (insect allergy)
• vomiting (insect allergy).

Avoid self-diagnosis. The signs and symptoms of allergy are shared by many other conditions. It is important to see a doctor or a specialist in clinical immunology/allergology for a professional diagnosis and treatment.

03 Allergies: diagnosis

The best clinics in Switzerland carry out a full diagnostic work-up to find the cause of an allergy. Using special allergy tests, the doctor can determine whether allergies are present and, if so, which ones. The patient is exposed to various allergens and the body’s reaction is observed. This is, of course, done in a controlled manner and only in small quantities.

The following allergy tests are commonly used:

• Blood test: the immune system produces specific antibodies against allergens it presumes to be harmful. These can be detected in the blood and are called IgE antibodies. In some types of allergy, the immune system forms special defence cells instead. These can be detected with what is known as a lymphocyte transformation test.
• Patch test: special skin patches carrying possible triggers are applied to the patient’s back or forearm. If the patient is allergic to a substance, the skin reacts with redness, swelling or blisters.
• Prick test: like the patch test, the prick test is a skin test. The doctor places drops of allergens on the inside of the forearm and then lightly pricks the skin with a fine lancet. If there is an allergy, redness, itching or a rash appears.
• Intradermal test: the intradermal test works in a similar way to the prick test and is suitable for weak allergens. These are injected directly under the skin of the back.
• Provocation test: under medical supervision, the patient receives a small, gradually increasing amount of the suspected allergen – by mouth for food allergies or by inhalation for respiratory allergies – and the doctor monitors the reaction (after inhalation, by measuring lung function).

Common allergens

A substance in the environment that can cause an allergic reaction in susceptible people is called an “allergen”. There are many different allergens, but they all have one thing in common: protein. Some allergens contain no protein to begin with but bind to a protein once inside the body, triggering an allergic reaction.

Common allergens include:

• foods – such as crustaceans, eggs, fish, milk, peanuts, tree nuts (for example almonds, cashews, pecans and walnuts), sesame and soya products
• plants – grass and plant pollen
• medicines, including prescription medicines (for example penicillin), over-the-counter medicines (for example aspirin) and herbal preparations
• insects – such as dust mites and the venom of bees, ticks, ants and wasps
• moulds – for example fungal and mould spores
• animal dander – for example the hair and skin flakes of pets such as cats and dogs
• chemicals – including industrial and household chemicals and chemical products such as latex rubber.

Food allergies

A food allergy is a group of symptoms caused by eating food that provokes an excessive and abnormal reaction in the body. Whether a food allergy develops depends on the body’s innate or acquired tendency to produce immune proteins on contact with food ingredients. The substances that most commonly cause food allergies are cow’s milk proteins, hen’s eggs, wheat, nuts, citrus fruits, seafood and soya.

Food allergies have a variety of symptoms. They mainly affect the digestive system, with nausea, vomiting, abdominal pain and, in the very young, colic. Skin changes may also occur – redness, itching and hives. In severe cases, anaphylactic shock can develop: a very strong, life-threatening reaction of the immune system that requires emergency medical care. The treatment of food allergies is based above all on diet, that is, removing allergenic foods from the menu.

Inhalant allergy

Inhalant allergies are caused by microscopic airborne particles, especially:

• pollen from trees, grasses and weeds (for example birch, poplar, oak, mugwort, orache, alder, willow, nettle and plantain);
• fungal and mould spores;
• house dust mites, especially species of the genera Dermatophagoides and Euroglyphus;
• animal hair – most often from cats, dogs, guinea pigs, rabbits, hamsters and horses.

By timing of exposure and origin, allergens are divided into outdoor (so-called seasonal) allergens, encountered outside, for example in a garden or park, and indoor (so-called perennial) allergens, to which you are exposed at home.

The most frequent symptoms of inhalant allergy are a recurrent runny nose, bouts of sneezing, an itchy nose, a scratchy throat, recurrent conjunctivitis, watering and itchy eyes, shortness of breath and a dry, exhausting cough. People with this type of allergy also often experience frequent upper respiratory tract infections that are difficult to treat.

Inhalant allergies are mainly treated with medication: antihistamines, which block the action of histamine, the substance responsible for the allergic reaction, and corticosteroids, which suppress the body’s inflammatory response.

If symptoms such as shortness of breath, a wheezing cough or difficulty breathing (especially when breathing out) appear, you should see a doctor, as these symptoms may indicate developing bronchial asthma. Asthma may require periodic or continuous use of inhaled medication.

Contact allergy

A contact allergy results from direct contact between the skin and an allergenic substance. This type of allergy is most often caused by:

• dyes;
• metals such as nickel, chromium and cobalt (for example jewellery, coins, belt buckles, fasteners, hooks and buttons);
• cosmetics (for example fragrances and preservatives);
• plastics (for example latex, plastic, polycarbonate, rubber and polyethylene).

The symptoms of contact allergy are skin changes such as redness, itching, peeling of the epidermis, rashes, hives, blisters and sores. Because the clinical picture is similar, contact allergy is sometimes confused with irritant eczema. Its treatment is based above all on removing the allergenic factor. Proper skin care is also very important, ideally with emollients (substances that moisturise and hydrate the skin and soothe itching and inflammation). Medication is sometimes needed – antihistamines, disinfectants, glucocorticosteroids, and antibiotics in the event of secondary superinfection of the skin lesions.

Cross-allergy

Cross-allergy is the appearance of identical or similar symptoms in response to an agent to which a person is not allergic but which is structurally similar to one to which they are. Specific antibodies produced against one allergen can cross-react with other allergens. One example is a food allergy to certain products in people who are allergic to pollen. Here are some examples of cross-allergy:

• birch pollen – nectarine, apricot, apple, pear, cherry, kiwi, plum, carrot, potato, dill, nuts, almonds, celery;
• mugwort pollen – apple, kiwi, celery, carrot;
• grass pollen – tomato, potato, melon, watermelon, oranges, peanuts;
• wheat – oats, rye, sesame;
• cow’s milk – sheep’s, goat’s and mare’s milk;
• hen’s eggs – chicken meat, duck, goose and turkey eggs;
• peanuts – soya beans, green beans;
• prawns – lobster, crab, crayfish;
• cod – herring, flounder, mackerel.

Allergies can have a wide range of triggers and show themselves through numerous symptoms that are often underestimated or overlooked. This diversity means that many people are unaware of their allergy. Yet if allergic diseases are not diagnosed and treated in time, the course of the illness can worsen considerably.

That is why early diagnosis of allergies matters. The diagnostic pathway usually comprises several stages that build on and complement one another.