Sublingual immunotherapy: An important breakthrough for allergic veterinary patients

In all the excitement of new dermatology drugs both recently released and soon to be available, Thomas Lewis II, DVM, DACVD, doesn't want veterinarians to miss out on what he considers one of the top breakthroughs in the treatment of atopic dermatitis in the last few years: the use of sublingual immunotherapy.

The injectable form of immunotherapy, of course, has been available for decades, and any practitioner who's treated an allergic dog using this protocol is familiar with its pros and cons.

Dr. Thomas Lewis“My own dog was on injectable immunotherapy for several years,” Lewis told dvm360 recently. “The injections worked, but he hated his shots. My wife hated holding him, and I hated giving them. Sublingual is a form that avoids the needles. And for many pet owners and many allergic dogs, that's a welcome change.”

And the benefits extend beyond decreased pain and increased ease of administration, says Lewis, who practices at Dermatology for Animals in Gilbert, Arizona. “There are some patients who have failed injectable immunotherapy who have a positive response to sublingual immunotherapy,” Lewis says.

The response can occur more quickly, as well. Rather than waiting for months to see a response to injectable immunotherapy, veterinarians often see improvement to sublingual administration in 30 days or less. “I have had patients respond to their sublingual drops within the first one and two weeks,” Lewis says.

Another feature Lewis highlights is safety. Patients who have had an adverse reaction to injectable immunotherapy usually tolerate the sublingual form much more readily. “Even patients who've had anaphylactic reactions have done just fine when we switched them over to sublingual,” he says.

Plus, the human literature shows one human fatality for every 6.4 million immunotherapy injections, but “there has never been a fatality to sublingual, according to last review I read,” Lewis says.

Of course, the limitations of sublingual immunotherapy remain the same as those associated with injectable immunotherapy. First and foremost is the challenge of correlating test results with the patient's exposure patterns. “We'll see crazy things in allergens if the clinician is not really supervising that process,” Lewis says. “It makes no sense to have a patient who is itchy year-round yet we only find a couple of tree pollens in their extract. So correlating those test results with the patient's pattern is of the utmost importance.”