Adults with excessively dry hands were four times more likely than healthy counterparts to fail computerized fingerprint verification tests in a small new study from Malaysia, according to an article from Reuters Health.

Fingerprints are still the most common unique personal trait used to identify an individual, although other measurable unique biological features include the iris of the eye and keyboard typing patterns. Analysts have projected that the global biometrics market will be worth $16 billion in four years.

Cracked or swollen skin can disrupt the unique crevice patterns found within an individual’s fingerprints, which are increasingly used for security checks at banks or to access buildings, the article reports.

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According to an earlier study from Denmark, an estimated 15 percent of people worldwide will suffer from hand dermatitis – skin inflammation usually caused by an allergic reaction.

In the Malaysian study, the research team recruited 100 patients with dermatitis either affecting either thumb and 100 participants with healthy fingers as a comparison group. Each patient had three attempts with each thumb to get an accurate match with a fingerprint scanner – 27 of 100 dermatitis patients failed fingerprint verification tests, compared to only two participants in the comparison group, the article says.

Eighty-four in the patient group had areas on their thumbs where prints were missing or skin appeared mottled due to rough skin. The larger area of so-called dystrophy, the article says, the more likely a patient was to fail the test.

Both groups had abnormal white lines in the prints, caused by wrinkles or cuts. However, when the lines appeared in prints, dermatitis patients had a greater number of them. Researchers guess that the cuts may ruin the pattern of tiny ridges within thumbprints.

Although most hand dermatitis can be resolved with topical creams, people who have allergic contact dermatitis – the majority of patients in this study – may struggle with constant exposure to irritants in the workplace, the article says. This would include healthcare workers, who frequently wash their hands, a mechanic who works with greasy bolts and nuts inside an engine or a chef who slices lots of onions or garlic between the thumb and index finger may develop hand dermatitis.