House dust mites and severe atopic dermatitis: A new connection

Patients with severe atopic dermatitis who have lower serum vitamin D levels have a high sensitivity to house dust mites, which can aggravate their condition, a new study shows.

The findings â€” which were described by the authors significant, but preliminary â€” appear in the August issue of the Annals of Dermatology.

“Patients with low serum vitamin D levels have an increased risk of house dust mites sensitization by increased penetration of house dust mites through broken skin barrier. Findings of this study suggest that vitamin D level may affect sensitization,” wrote the authors who were led by Do Won Kim of the National University School of Medicine, Korea.

The study was small, with only 43 men and 37 women of which 43.8% had mild to moderate disease and 56% had severe atopic dermatitis. Laboratory tests included serum 25-hydroxyvitamin D3, total immunoglobulin E (IgE), and specific IgE antibody titer against Dermatophagoides farinae and D. pteronyssinus.

The authors suggest that high sensitivity to house dust mites may aggravate an already dysregulated immune system associated with the development of severe atopic dermatitis.

Previously published studies have shown a connection between vitamin D insufficiency and deficiency with the development of allergies. But there is little evidence that connects vitamin D with the development of allergic skin diseases and the severity of these diseases, yet researchers continue to contemplate this connection. Some studies show an inverse association between vitamin D and atopic dermatitis severity, while other studies show no significant correlation between the two.

It is known that vitamin D has a role in both the innate and adaptive immune systems. Research has shown that the more defective the immune system, the weaker antimicrobial defense systems become which comprises the integrity of the epidermal barrier.

If vitamin D disrupts the immune system, it is possible that it may impair the body’s natural defense mechanisms against common household allergens, such as the house dust mite. The authors of this study set out to evaluate the correlation between serum vitamin D levels and sensitization to house dust mites by atopic dermatitis severity.

THE FINDINGS

The mean serum vitamin D level of patients in the study was 19.29±8.03 ng/ml. There was no significant difference between serum vitamin D levels between patients with severe AD (19.46±8.10 ng/ml) and mild to moderate AD (18.98±7.97 ng/ml, p=0.72). But for patients with severe atopic dermatitis, the mean total serum IgE level (2,011.96± 993.89 kU/L) was significantly higher than that in patients with mild to moderate AD (260.88±431.54 kU/L, p＜0.05).

Patients with severe atopic dermatitis who had significantly lower serum vitamin D levels were also found to have high D. farina sensitization (p＜0.05). The same was true of D. pteronyssinus in which patients with severe disease, the presence of high D. pteronyssinus sensitization usually equated with lower serum vitamin D levels with statistical significance (p＜0.05). No such association was found in mild to moderate disease.

REFERENCE

Yong Hyun Jang, Hyun Bo Sim, Sun Young Moon, et al. "House Dust Mite Sensitization is Inversely Associated with Plasma 25-Hydroxyvitamin D3 Levels in Patients with Severe Atopic Dermatitis," Annals of Dermatology. August 2017. https://doi.org/10.5021/ad.2017.29.4.400