Dear Editors,

We read with interest the article titled ‘Long-term effects of allergen-specific subcutaneous immunotherapy for house dust mite induced allergic rhinitis’, by Sahin et al.,Reference Sahin, Dizdar, Dinc and Cirik¹ in your esteemed journal. This is a well-written article, and we would like to commend the authors on a good effort, as long-term follow up of patients is often so difficult in clinical practice. The article does throw up a few issues though, and we would like to add our views on some of them here.

The study involves the follow up of 20 patients over a 10-year period. We do understand the significant problems encountered in any follow-up study, especially in terms of patient compliance for follow up. However, given the small sample size, we feel the significance of the results should be considered cautiously. As allergic rhinitis is such a common condition, further studies involving a much larger sample size would lend further significance to the results and would definitely help in the shaping of future policies in regard to allergen-specific subcutaneous immunotherapy. Even still, we do laud the authors for a commendable effort.

The fact that subcutaneous immunotherapy is especially efficacious in patients with allergic rhinitis and significantly improves their quality of life has been quite well established in multiple meta-analyses.Reference Passalacqua and Durham² However, as the authors rightly pointed out, the need for repeated injections and the real risk for serious adverse effects associated with subcutaneous immunotherapy does seem to limit its widespread use. In this context, the future of immunotherapy may belong to sublingual immunotherapy. A study by Wang et al.Reference Wang, Chen, Cheng, Li, Yuan and Lu³ showed a fast onset of action with sublingual immunotherapy in house dust mite induced allergic rhinitis. With an average adherence rate of 75–90 per cent,Reference Incorvaia, Mauro, Ridolo, Puccinelli, Liuzzo and Scurati⁴ sublingual immunotherapy appears to be a more attractive choice for future studies regarding the long-term outcomes of immunotherapy.

Apart from sublingual immunotherapy, other routes of immunotherapy administration, such as nasal and oral immunotherapy, need to be explored in greater detail. Fewer adverse effects and better patient compliance may be crucial to allergic rhinitis patients being free of asthma.