Local immunotherapy in allergy: prospects for the future

Sublingual immunotherapy in allergy is a promising method invented in its preliminary form almost 100 years ago, but applied in practice for only several years. A continuously increasing number of controlled studies indicate the efficacy of this method, but nevertheless numerous questions concerning immunological mechanisms, mode of application or long-term (side) effects remain to be answered and are responsible for keeping clinicians from prescribing it. Thus far, only a few studies compare the local and subcutaneous application of immunotherapy, but since the most efficient mode of application still remains far from being determined, such comparisons cannot be used for a general or definite recommendation of one of both therapies. The studies also fail to take into consideration patients' compliance or acceptance of different types of therapies depending upon the previous duration and state of allergy. Although the acquiescence of local immunotherapies by physicians and patients is increasing, the topic will continue to offer material for years of emotional and scientific discussions.