HOUSTON – Whether atopic dermatitis should be treated with allergen immunotherapy is still a matter of debate, as high-quality trial evidence remains scant, but clinical practice is starting to recognize the potential use of subcutaneous and sublingual immunotherapy for certain presentations of the disease.
For patients with allergy to house-dust mites, evidence is leaning toward a role for subcutaneous immunotherapy (SCIT) in severe forms of atopic dermatitis (AD), and to sublingual immunotherapy (SLIT) for milder forms, researchers said.
At the annual meeting of the American Academy of Allergy, Asthma, and Immunotherapy, Dr. Linda Cox, an allergist in private practice in Fort Lauderdale, Fla., said that poor trial evidence and a lack of standardization in outcome measures have hindered a better understanding of when SLIT and SCIT might be indicated in atopic dermatitis. Systematic reviews have failed to offer compelling evidence for its efficacy.
This is why current practice guidelines, published in 2012, say only that clinicians “might consider” allergen immunotherapy in selected patients with AD with aeroallergen sensitivity, and the research community has been striving to standardize outcome measures using two published eczema scoring systems, EASI (Eczema Area and Severity Index) and SCORAD (Severity Scoring of Atopic Dermatitis). Dr. Cox, part of the AAAAI/American College of Asthma, Allergy, and Immunology joint task force on allergen immunotherapies, said new clinical guidelines in progress would likely attempt to better define the role of SLIT and SCIT in atopic dermatitis.
Dr. Cox and another speaker at the conference, Dr. Moises Calderon, both pointed to house-dust mite allergy with AD as the most promising indication for immunotherapy in AD. A closer look at the few well-designed trials that have been conducted so far reveal the potential for a better-defined role for SLIT and SCIT, they agreed.
Dr. Calderon of Imperial College London identified four important trials dealing with this issue. The first was a German study of adults with AD aggravated by house-dust mites (n = 168) randomized to SCID or placebo and treated for 18 months. The study revealed no statistically significant differences for the treatment group as a whole, but a subgroup of patients with severe AD showed a statistically significant reduction of SCORAD disease scores by 18% (P = .02), compared with placebo (J Allergy Clin Immunol. 2012;130:925-31).
An Italian trial enrolling house-dust mite–sensitive children with AD (n = 56, randomized 1:1 to treatment with SLIT or placebo) found a significant difference in SCORAD from baseline (P = .25) between the children treated with SLIT and the placebo group starting 9 months after treatment. However, the difference was seen in patients with mild or moderate disease only; minimal benefit was found for children with severe disease (J. Allergy Clin. Immunol. 2007;120:164-70).
Dr. Calderon pointed to two additional studies published that also suggested benefit. The first was an open-label Colombian study enrolling children and young adults (n = 60). Of the 31 patients randomized to treatment with SCIT and topical therapies (controls received only topical treatment), the treatment group had significant SCORAD-measured improvement, compared with the control group (P = .03). At 1 year the active group also used topical steroids and tacrolimus significantly less (P = .02), and also had a significant increase in mite-specific IgG4 (doi:10.5402/2012/183983).
Dr. Calderon also mentioned a recent observational study from Poland that looked at long-term follow-up of a group of 15 AD patients treated with SCIT between 1995 and 2001 and followed for 12 years. The results suggested that SCIT may be associated with lasting improvements even after treatment termination (Eur. Ann. Allergy Clin. Immunol. 2015;47:5-9).
Both Dr. Cox and Dr. Calderon agreed that more and better evidence was needed to understand when and how SLIT and SCIT can work in atopic dermatitis. “AD is a heterogeneous disease, and immunotherapy cannot be a treatment for all types of atopic dermatitis – no one treatment is probably effective for all types of AD,” Dr. Cox cautioned. But “the direction of therapy is headed toward some acceptance.”
Dr, Calderon concurred. “We are on the way to acceptance. But new studies will be key,” he said.
Dr. Cox disclosed financial relationships with Greer and Circassia. Dr. Calderon disclosed no conflicts of interest.