Allergic rhinitis is characterised by red, itchy eyes, a blocked and runny nose, and sneezing. The most common causes of allergic rhinitis are different pollens (grass and tree), house dust mites, mould and animal dander. Allergic rhinitis can be intermittent (such as hay fever) or persistent (all year round). The treatment of allergic rhinitis depends on its severity and duration, and is usually based on the use of antihistamines and nasal corticosteroids. If these drugs cannot control symptoms immunotherapy is recommended. Immunotherapy involves the administration of gradually increasing doses of the allergen over a period of time to desensitise the patient. It is the only known treatment that modifies the immune response and treats the cause rather than the symptoms.
In reviewing 60 trials we found a significant reduction in symptom and medication scores in patients treated with sublingual immunotherapy compared to placebo. There were no serious adverse reactions reported in the included trials and no patient needed the use of adrenaline. This updated Cochrane Review therefore reinforces the conclusions of the earlier review in confirming the efficacy and safety of sublingual immunotherapy.