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Specific hyposensitization by means of sub-cutaneous injections

par Odile


Specific hyposensitization
by means of sub-cutaneous injections
– Information form –

You are to start a specific hyposensitization treatment, which is meant to reduce your allergy related symptoms : rhinitis and/or asthma, urticaria, Quincke oedema, shock or other manifestations. This kind of treatment might also be advised to treat venom allergies (bees and wasps), in case of very severe reactions.

Aim of the treatment
Specific hyposensitization allows to diminish allergic reactions due to contact with a substance named allergen to which you are sensitized. This treatment is a long-term one.

Description of the treatment
The treatment involves the administration of slowly increasing doses of one or several allergen extracts. Usually, the shots are done, at first, once a week, then progressively less frequently. The optimal dose can be reached within a few months’ time. A maintenance treatment consists of spaced out booster doses (about every month).
The day of the shot, the injected dose, and also a possible reaction, have to be registered in the personal booklet remaining in your possession.
To show long term efficiency, a hyposensitization treatment should be pursued at least during 3 to 5 years. If no proof of efficacy can be observed 6 months after reaching the optimal dose for the perannual allergens, or else after two pollen seasons, the treatment shall be stopped.
In certain circumstances (bee or wasp venoms), as far as controlled in hospital, progression can be faster: from several hours to a few days. Booster treatment has nevertheless a duration of 3 to 5 years. Venom hyposensitization shows efficacy in more than 90% of the cases encountered.

Possible risk
Local reactions (such as swelling, blotching, or itching) may appear within a few hours after the shot. They are to disappear after a 24 to 48 hours delay.
General reactions are very scarce. They may occur after any injection, especially at high doses. They increase the allergy symptoms. In case of a late reaction after leaving the allergist’s practice, a doctor has to be called very urgently, and advised of the hyposensitization shot that the patient has just received. All of these incidents must at any time be declared to your doctor.

Shock reactions are rather exceptional, but always severe: urticaria, great breathing difficulty and uneasiness. They require immediate treatment to prevent from a risk which could be vital. The arising of such an occurrence within a few minutes after a hyposensitization injection necessarily requires your staying in the allergist’s practice for half an hour after the shot. This situation allows very quick intervention when necessary.

Precautions to be observed
The injections shall take place in the allergist’s practice, and will be performed either by the allergist himself, or by a nurse under his control.
Before injection: you have to inform the doctor of all possible events following the preceding injection, of any new prescription of drugs, as well as of any recent increase of your symptoms.
After injection: You have to stay for 30 minutes in the doctor’s waiting room, which you may leave only after clinical control. Also, you have to prevent from heavy physical exercise within the hours following the shot.

A moderate reaction on the shot spot can be eased by an antihistaminic medication, which has to be mentioned to your allergist at your next visit.

A general reaction occurring after the caution delay dictates an immediate return to the medical center, a telephon call to an emergency center, or else a contact with the SAMU (tel. Number 15, or 112 on your handy).

Informations to be provided to your doctor
Before any hyposensitization injection, you must be ascertained that your allergy is under control with adequate treatment. If not, or if you are otherwise diseased, let it know to your allergist.
A beta-blocker, for instance – be it presented in tablets or eye lotion – will obstruct the efficacy of an emergency treatment in case of a strong allergic reaction. This beta-blocker might as well be prescribed by your GP, by a heart specialist, or else by an ophtalmologist. Of this you must inform your allergist. Also you have to signal when you take any medication like a converting enzyme inhibitor – or more generally any new medical treatment.

For emergency or further information, please call this number: ……………………………….

Enlighted consent of the patient
My allergist informed me in great details of a hyposensitization treatment. He gave me all precisions concerning the aims, risks and alternative treatments, which I am aware of. Thus I give my consent to undertaking such treatment.

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