Retrospective Analysis on the Effects of House Dust Mite Specific Immunotherapy for More Than 3 Years in Atopic Dermatitis

Abstract

Purpose: In extrinsic atopic dermatitis (AD), house dust mites (HDM) play a role in eliciting or aggravating allergic lesions. The nature of skin inflammation in AD has raised a growing interest in allergen-specific immunotherapy (SIT). Thus, we assessed clinical improvement and laboratory parameters for evaluation of the benefit of long-term SIT.

Materials and methods: A total of 217 AD patients who were treated with SIT for at least 3 years were retrospectively assessed, by using their investigator global assessment, pruritus scores, loss of sleep (LOS), total serum IgE, and eosinophil counts collected. Patients were additionally classified into subgroups according to age, initial AD severity and mono- or multi-sensitization to include different individual factors in the evaluation of SIT efficacy. Lastly, we compared laboratory data of good responders to SIT with that of poor responders to SIT.

Results: Improvement after SIT therapy was observed in 192 out of 217 patients (88.4%). Among these patients, 138 (63.5%) achieved excellent, near-complete or complete clinical remission. Significant reduction of pruritus, LOS, and the mean value of total serum IgE were observed (p<0.01). Better outcome was found in patients younger than 12 years of age (p=0.024). Patients with moderate to severe AD showed better treatment outcomes (p=0.036). Patients sensitized only to HDM had the better response to treatment, but SIT was also effective in multi-sensitized groups (p=1.051). No significant differences in baseline laboratory results were observed between good and poor responders (p>0.05).

Conclusion: We emphasize the usefulness of long-term HDM SIT as a disease-modifying therapy for AD.

Keywords: Atopic dermatitis; allergen-specific immunotherapy; house dust mites.

Fig. 1. Overall treatment response of allergen-specific immunotherapy. Among 217 patients, 98 patients (45.2%) showed clinical remission, 40 patients (18.3%) exhibited excellent response. Parenthesized numbers refer to estimated overall clinical response scores.

Fig. 2. Subgroup analysis according to patients' age. Patients with age under 12 showed better treatment response when compared with adolescents and adults. ^*p<0.05. ns, not significant.

Fig. 3. Subgroup analysis according to the number of allergen sensitization. Patients who were only sensitized to HDM were defined as monosensitized patients, and multi-sensitized patients showed positive results not only with HDM but also with other food and inhalant allergens. Monosensitized patients presented a tendency to respond better than the multisensitized group but did not show statistical significance (p>0.05). HDM, house dust mite.