South Korea has seen the number of atopic dermatitis patients rise, especially among women, data showed Wednesday.

According to the state-run National Health Insurance Service, the yearly average number of patients receiving atopic dermatitis treatment hit 1.04 million between 2008 and 2012, with over half of them women.

Atopic dermatitis is an itchy skin disorder that is inflammatory and non-contagious. Patients show allergic reactions to particular foods or inhaled substances.

The exact cause is unknown but experts suspect it to be hereditary or an immune system problem. About 70 to 80 percent of cases were found to run in families, the agency said.

By age, nearly half of patients were under the age of 9, with 32.8 percent infants under 4. This means that 15 out of 100 toddlers have received atopic dermatitis treatment.

The number of patients under 30 dropped on average by 3.7 percent a year.

While most of the symptoms were found mild, the number of severe cases also increased, the report said. In 2012, the number of hospitalized patients reached 1,375, up 53 percent from 2008.

By region, Jejudo Island, Seoul and its surrounding metropolitan areas had the most patients, with more than 2,000 people with atopic dermatitis in these locations.

In order to prevent breakouts of the disease, the NHIS stressed the importance of alleviating skin dehydration. It suggested that patients should avoid using soap or detergents that may cause irritation while frequently using moisturizers. The agency also warned that pollen, mites and cockroaches appeared to worsen the symptoms.

By Lee Hyun-jeong  (rene@heraldcorp.com)