Can dust mite allergy be treated with a pill?

It’s something people don’t like to think about, but it’s a fact that dust mites are all around us. These mites are microscopic relatives of spiders and ticks who live off of skin cells that we shed. It is almost impossible to eradicate them, and even the cleanest home has dust mites. Though dust mites do not bite us or cause rashes, they are a common cause of year-round allergy symptoms such as runny nose, itchy eyes, and sneezing. People with dust mite allergy have a persistently itchy nose even when not physically around dusty objects.

A recent study has shown that a new way of treating dust mite allergy is effective and safe. What do you need to know about this treatment, called sublingual immunotherapy?

Dust mite allergy and management

The first-line management of dust mite allergy is always to manage the environment. Beyond cleaning (wiping surfaces, washing linens), encasing any upholstery that cannot be washed will reduce the impact of dust mites, which like to burrow into soft cushions and mattresses. Zippered, allergen-resistant encasements for pillows, mattresses, and box springs can be purchased and are an effective measure in the fight against these microscopic mites. Over-the-counter allergy medications such as steroid nasal sprays and antihistamines can also be helpful.

For decades, when these measures have failed, we have used allergy shots, also called subcutaneous immunotherapy (SCIT), to treat dust mite allergy. This is an effective but burdensome treatment, which involves weekly shots for approximately six to eight months, and then monthly shots for approximately three to five years. The shots must be given in a doctor’s office, where a physician is present, because of the risk of allergic reactions. This is an inconvenience during normal times, but even more so during the pandemic.

SLIT: The convenient new way to treat dust mite allergy

Sublingual immunotherapy (SLIT), which was approved by the FDA in 2017, is the newest treatment option for treatment of dust mite allergy. It is sold under the brand name Odactra in the United States. Just like SCIT, SLIT trains the immune system to no longer recognize dust mites as an allergen. The biggest benefit compared to SCIT is the convenience: this is an oral medication that is taken at home.

The daily medication is placed under the tongue, and many patients complain of a bit of tingling in the mouth or an odd taste. And because there is a risk of an allergic reaction, you must carry an EpiPen at all times so that you can treat yourself if necessary. I teach all of my patients on SLIT to recognize and treat anaphylaxis. Your doctor may not prescribe SLIT if you cannot use epinephrine for any reason, such as severe heart disease. SLIT is expensive, and insurance approval has been a major barrier for my patients, despite my best efforts.

Study finds SLIT is safe and effective

A recent study, published in the Journal of Allergy and Clinical Immunology, showed the safety and efficacy of dust mite SLIT compared to placebo. This was an international study, with about 800 patients in the placebo group and 800 patients in the treatment group. At the end of one year, patients who had received dust mite SLIT had fewer nose and eye symptoms and had used fewer medications to control allergy symptoms, compared to those in the placebo group. The study also demonstrated safety, with no one having anaphylaxis and only four uses of epinephrine in the SLIT group. Although the study only extended out one year, SLIT would likely be used for three to five years, the same duration as SCIT.

SLIT for ragweed and grass is also FDA-approved, but we don’t combine SLIT treatments, so the best candidate for dust mite SLIT is someone who is allergic only to dust mites. A person with many allergies is better served by SCIT, which can address several allergies at once.

I’m excited about this new method of treating my patients, and I’m hopeful that similar drugs for other allergens will be on the horizon.