Immunotherapy for allergies

Allergen immunotherapy is a treatment designed to address the underlying cause of allergies rather than just controlling symptoms. It works by gradually training the immune system to become less sensitive to specific allergens, offering longer-term relief for people whose symptoms persist despite standard treatments.

What is allergy immunotherapy?

Allergy immunotherapy involves regular exposure to very small, controlled amounts of an allergen. Over time, this helps the immune system develop tolerance, reducing the exaggerated allergic response that causes symptoms such as sneezing, nasal congestion, itchy eyes or asthma flare-ups.

Unlike antihistamines or steroid sprays, which manage symptoms temporarily, immunotherapy aims to modify the course of allergic disease itself.

Which allergies can be treated?

Immunotherapy is most commonly used for inhaled allergies and insect venom allergy. It is not routinely used for food allergies outside specialist settings.

Commonly treated allergies include:

pollen allergies such as hay fever
house dust mite allergy
animal dander allergy
mould allergy
wasp or bee venom allergy

It’s particularly helpful for people with moderate to severe symptoms that interfere with daily life or sleep, or when medication causes side effects or is ineffective.

How is immunotherapy given?

There are two main forms of allergen immunotherapy.

Subcutaneous immunotherapy involves injections given under the skin, usually in the upper arm. These are administered at regular intervals in a specialist clinic, starting with very low doses that are gradually increased.

Sublingual immunotherapy is taken as tablets or drops placed under the tongue, usually at home after the first supervised dose. This option is widely used for pollen and house dust mite allergy.

Treatment typically continues for three to five years to achieve long-lasting benefit.

What benefits can patients expect?

Immunotherapy can significantly reduce allergy symptoms and the need for regular medication. Many patients also experience improved asthma control if their asthma is allergy-driven. Importantly, the benefits often persist for years after treatment has finished.

In children and young adults, immunotherapy may also reduce the risk of allergies worsening over time or progressing to asthma.

Safety and side effects

Allergy immunotherapy is generally safe when prescribed and monitored by a specialist. Mild side effects such as local swelling, itching, or mouth irritation are common, particularly at the start of treatment. More severe allergic reactions are rare but are the reason why treatment is initiated and overseen by experienced allergy teams.

A careful assessment is essential before starting, especially for people with asthma or other medical conditions.

When should immunotherapy be considered?

Immunotherapy is usually considered when symptoms remain poorly controlled despite optimal medication and allergen avoidance, or when long-term medication is not desirable.

Diagnosis must be confirmed with appropriate allergy testing before treatment is recommended.

A long-term approach to allergy management

Immunotherapy represents a shift from symptom control to disease modification. For carefully selected patients, it offers a proven, evidence-based way to reduce allergic symptoms, improve quality of life, and achieve lasting relief under specialist care.