Sublingual Allergic Rhinitis Treatment Is Safe & Effective

Allergic rhinitis is can be intermittent (as with hay fever) or persistent (year-round or perennial rhinitis).  Sublingual – i.e. under-the tongue – immunotherapy has been used with enthusiasm in Europe for a number of years.  However, US allergologists are less wholehearted in their evaluation.  Perhaps their minds will be changed by a review of SLIT (sublingual immunotherapy) for allergic rhinitis published in the Cochrane Review. 

SLIT involves the under-the-tongue administration of gradually increasing doses of the responsible allergen for the subject’s rhinitis over a period of time, to desensitize the patient.  The allergen can be given in either pill or liquid form.  (In earlier times such treatment was given by subcutaneous injection, and occasionally resulted in side effects – anaphylaxis- that required treatment using adrenaline injections.) 

The reviewers found 60 randomized, double-blind, placebo-controlled trials of SLIT in adults or children.  Most of them had allergic rhinitis that was resistant to treatment with antihistamines and nasal corticosteroids.  The allergens included pollens, dust mites, and cat allergens.  49 of the trials were suitable for pooling in meta-analyses; they included 2,333 patients on SLIT, and 2,256 placebo patients.

Overall, there were statistically significant reductions in symptoms (roughly halved) and medication requirements (reduced by roughly two-thirds) in the SLIT patients, when compared with results in the placebo control patients.  None of the trials reported severe side effects or anaphylactic reactions with either SLIT or placebo, and no adrenaline injections needed to be given.  Mild side effects were reported with SLIT, and were mostly confined to the upper respiratory tract – nose, mouth, pharynx, and larynx.

The authors conclude that sublingual therapy is “now established as a viable alternative to allergen injection immunotherapy, with a significantly lower risk profile and, on the basis of meta-analyses, little difference in overall efficacy.”  If you suffer from allergic rhinitis, ask your allergist about SLIT;  maybe she/he has also read this review.