Allergic reactions due to drug use are reactions caused by taking a drug unpredictably.

They are the third leading cause of care at allergology clinics and account for 5%-10% of all adverse drug reactions of allergic origin. Their adverse effects range from a skin rash, itching and swelling of the lips and tongue to an anaphylactic reaction.

In the event of the supposed onset of an unexpected adverse reaction due to taking a drug, the specialist will perform an allergological study to determine and/or confirm the drug causing the reaction.

Allergic reactions to drugs are the third leading cause of care at allergology clinics.

The Immunotherapy, also known as allergy vaccines, consists of administering larger and larger doses of the allergen to which the patient is sensitised in an attempt to stimulate immunity and get the patient to tolerate natural exposure.

It is performed with a so-called allergen extract obtained from the natural allergen source: Pollen, mites, etc.

It has been confirmed to have a preventive effect on the onset of new sensitisations to allergens, and on the potential for the disease to progress from rhinitis alone to the added complication of asthma.

It may be performed subcutaneously, by injection, or sublingually.

It is indicated for rhinitis and asthma as well as allergies to bee and wasp stings. It may be used to treat allergies to pollen, mites, animal dander and fungi.

Normally it is not indicated for food allergies. In this case, avoidance remains the best therapeutic option. However, in some causes a treatment regimen of inducing oral tolerance to certain foods such as milk or eggs may be established.

Immunotherapy consists of two phases: an initiationphase and a maintenance . In the initiation phase, larger and larger doses of the allergen extract are given on a weekly basis until an effective dose is reached that stimulates the immune system without causing allergy symptoms. This point marks entry into the maintenance phase, where this dose is administered every 4 weeks for a period of 3-5 years.

Currently, there are products that greatly shorten the initiation phase by achieving the maintenance dose in a single day and require only monthly injections. These treatments are much more convenient for patients.

Beneficial effects on symptoms may appear three months into treatment, but are most often seen after a few more months, in the maintenance phase.

Allergy vaccines, or immunotherapy, are the only treatments that address underlying allergic disease.

Once an allergy is diagnosed, there are two types of treatment:

Environmental prevention measures

The first measure to keep an allergic reaction from being triggered is prevention, i.e. avoiding contact with the causative allergen. However, this is not always possible, especially in respiratory allergies.

Symptomatic treatment

Other measures would be using drugs to treat symptoms. The drugs most commonly used in the allergic process are antihistamines, corticosteroids, nasal decongestants, eye drops, etc. Taking these drugs to treat allergic diseases manages symptoms on a temporary basis.

Immunotherapy or vaccines for allergies

Allergy vaccines, or immunotherapy, are the only treatments for allergic diseases available on the market that address the underlying cause of the problem. This treatment not only relieves allergy symptoms and decreases the number of drugs to be taken, but also alters the natural course of the disease.

The three pillars of treating allergies are: Avoidance of the Allergen, Treatment of the Symptoms and Immunotherapy Vaccines.

The first diagnostic element that a specialist uses to diagnose allergic disease is the medical history which includes symptoms and their potential relationship to allergens, relevant characteristics of the patient’s home, existence or non-existence of a family history, and other information.

Next, using the medical history and the examination as a guide, skin tests are performed. These tests attempt to reproduce an allergic reaction on the skin by means of inoculation with the suspected allergens. A skin prick test, the most commonly used technique, consists of depositing a drop of allergen on the skin and then pricking it.

At times, depending on the allergen and/or signs and symptoms an intradermal reaction test is used. In this technique, a tiny amount of allergen is inserted into the skin using an insulin syringe.

Both tests are performed on the anterior forearm, are read after 15-20 minutes and always include a negative control and a positive control to establish a standard for comparison.

Sometimes, as an additional test, the presence of IgE antibodies in blood is examined and the specific IgE to a particular allergen or to a certain protein thereof is quantified.

When a confirmatory diagnosis is not reached with the above tests, provocation tests are performed. These attempt to reproduce the potential allergic reaction in the affected organ — the nose, conjunctiva or bronchi — by administering the allergen under highly controlled circumstances.

For the most part, allergies are diagnosed through a good medical history and skin and blood tests.

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