Acaroid desensitisation for dust mite allergy

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What is dust mite desensitisation, and what does it involve?

Dust mite desensitisation (also known as immunotherapy) is a treatment used for severe nose inflammation that is caused by dust mite allergy. We recommend this treatment only where other measures have failed to work. ‘Acaroid’ is the brand name for the dust mite product that we use.

It involves giving regular injections of dust mite allergen in order to ‘reset’ the immune response. Over time, the allergy symptoms improve in most people.

Acaroid is given by injection in the upper arm.

The first phase of the treatment is known as ‘updosing’. We start with a very small dose, which is increased at each visit. You will need to attend every 1 or 2 weeks. It takes 8 sessions to reach the maximum dose.

The next phase of the treatment is known as ‘maintenance’. You attend once at 4 weeks and then every 8 weeks for top-ups. The treatment is complete after three years, and if it works, it gives you long-term protection.

Are there any side effects or risks?

Because you are allergic to dust mite allergen, the treatment can give you an allergic reaction. You must stay in the department for 30 minutes after you get your injections, as this is the risk period for severe reactions. If you do get an allergic reaction we will assess and treat anything that happens.

These reactions include:
• Local reactions: The injection site may itch, swell and go red. This is extremely common. It’s not dangerous: taking an anti-histamine tablet before you attend can help.
• Skin reactions: These include itching and hives. It happens at around 1 in ten thousand injection. Skin reactions usually happen within 30 minutes, but can happen after a few hours. The symptoms improve quite quickly and can be treated with anti-histamine tablets.
• Anaphylaxis: This is a severe reaction and includes rashes, swelling (for example, of the lips) and breathing problems or fainting. It happens very quickly after the injection. Severe allergic reactions to Acaroid are extremely rare, estimated at one in one million injections.
• Fatigue and tiredness on the day of treatment are another reported side-effect.

Are there any precautions?

You should stay in the department for 30 minutes after injections,as this is the risk period for severe reactions.
Please don’t come for immunotherapy if you are not well eg with infection.
If you have asthma, it should be well-controlled. If your asthma isn’t controlled on the day we may advise on treatment and delay the immunotherapy.
Vigorous exercise such as running, gym or exercise classes is not recommended straight after the dose.
Please let us know if you are taking B Blocker tablets.
Some people take an anti-histamine tablet before the appointment, which can help with the local reactions at the injection site.

Does the treatment work?

Out of every 10 people we treat, around seven to eight improve. Around two or three don’t feel any better and stop the treatment. It takes around six months to begin to work. If you aren’t any better by 12 months we’ll discuss other options.

It won’t get rid of the allergy completely, but can provide a useful improvement in symptoms.
If it works, the benefits are long-term, and continue after the treatment has finished.

What if I am pregnant or become pregnant during the treatment?

Pregnancy should be avoided during the updosing phase. However, if you become pregnant during the maintenance phase it’s not a problem.

Do I need to continue taking my usual medication?

Yes, please continue to take your usual medication. You may be able to reduce your medication once the desensitisation has started to work.

Where do I need to go for my treatment?

Desensitisation clinics are held in Main Outpatient Department, Royal Sussex County Hospital on Monday and Wednesday mornings. You will be given an appointment, but you don’t need to stick to the stated time: just turn up whenever convenient between 8am and 11.30am.

Who can I contact for further information and advice?

For further general information about desensitisation please enter ‘Allergy UK immunotherapy’ into a search engine.