Infections, Antibiotic Use Closely Associated With Late-Onset AD

Antibiotic use and infections are closely associated with late-onset atopic dermatitis (AD), according to a study published in Annals of Dermatology.

The researchers explained that recent studies have suggested that varying onset times of AD may differ by patient risk factors. Consequently, they conducted a nationwide population-based case-control study to investigate potential differences in the influence of antibiotic use or infections on AD risk according to patients’ onset ages.

They analyzed data of patients with AD from the Korean Health Insurance Review and Assessment Service. The researchers identified patients with AD as those who visited medical institutions with an AD principal diagnostic code (L20, L20.0, L20.8, and L20.9 in the International Classification of Diseases, Tenth Revision) more than twice in 6 months, defining AD onset as the patient’s first visit date. For comparison, the researchers created an age- and sex-matched control group for each patient with AD.

Similarly, the researchers identified patients’ infection episodes as their visits to medical institutes with a principal diagnostic code for infectious diseases. Also, they calculated the number of infection episodes and categorized them by organ involvement (eg, respiratory, gastrointestinal, otology, genitourinary, cutaneous, hematologic). Additionally, the researchers defined antibiotic cycles as a prescription of antibiotics, calculating the number of antibiotic cycles and the use duration.

white pills spilling from orange bottle | Image credit: neirfy - stock.adobe.com.

The study population consisted of 244,805 children with AD and an equal amount of sex- and age-matched healthy children. The researchers divided the patients according to onset age; the early-onset group consisted of patients who developed AD at younger than 2 years and the late-onset group consisted of those who developed AD at 2 years or older. Of the population, 216,563 (88.5%) developed AD before age 2 years.

The analysis showed that infections had a positive association with AD risk in both groups, but it was greater in those with late-onset AD (odds ratio [OR], 15.81; 95% CI, 12.40-20.17; early-onset group: OR, 1.56; 95% CI, 1.54-1.59).

Through further analysis, the researchers found that the association was strongest after skin infections in the early-onset group (OR, 1.95; 95% CI, 1.91-1.99) and respiratory infections in the late-onset group (OR, 15.57; 95% CI, 12.44-19.49).

Antibiotic use was also positively associated with AD risk in both groups, with the association stronger in the late-onset group (OR, 8.78; 95% CI, 7.42-10.40; early-onset group: OR, 1.07; 95% CI, 1.06-1.09).

Through their findings, the researchers concluded that the degree of association between the risk of AD and infection or antibiotic use was different as they found it to have a greater influence on late-onset AD. They also found that respiratory infections strongly affected late-onset AD development.

“Abnormal epithelial barrier or immune regulation can be the common underlying risk factors for AD and respiratory infection,” the authors wrote. “These immune responses may explain the strong association between respiratory infection and AD identified in this study.”

The researchers acknowledged their study’s limitations, one being that they could not find information on confounding factors like environmental influences or a personal or family history of atopic disorders. Despite these limitations, they concluded by noting that “the prevention of infections can be a way to reduce the risk of AD, especially late-onset AD.”

Reference

Choi CW, Yang BR, Suh DI, et al. Infections and exposure to antibiotics may affect the development of late-onset rather than early-onset atopic dermatitis. Ann Dermatol. 2023;35(4):325-328. doi:10.5021/ad.21.240