Research Should Focus More on Modifiable Risk Factors in Hand Eczema Disparities to Better Tailor Treatment

It is extremely important that physicians and other health care professionals become more familiar with risk factors for hand eczema among a more diverse patient population, according to the investigators of a new study, who stress the importance of focusing on modifiable risk factors to make inroads in tailoring treatments for the chronic inflammatory skin condition.

They published the findings of their review in Journal of Clinical Medicine.

“Given that endogenous factors cannot be avoided, but certain exogenous aspects can be modified, especially as the environment plays an important role in hand eczema flares,” they authors wrote, “it is helpful from a practical perspective to focus on addressing the modifiable risk factors.”

They added that although the relationship between occupational exposure and hand eczema has been explored, there is a lack of ongoing research exploring potential ethnicity-related disparities in hand eczema incidence and severity. From inception through February 10, 2023, the investigators systematically searched PubMed, EMBASE, Scopus, Cochrane Library, New England Journal of Medicine, and The Lancet for articles on studies that explored why certain ethnic groups may have a higher risk of dermatoses, including hand eczema.

Among the 79 publications included in the final analysis, the overall reasons identified for leading to disparities in hand eczema prevalence and severity were genes, differing skin physiology, cultural practices and customs, dietary habits and food preparation, climate, predominant occupations, socioeconomic factors, and differences in laws and regulations.

When discussing genetic causes, the investigators highlighted that mutations in the filaggrin gene have potential to increase hand eczema risk because they contribute to disruptions in the epidermal barrier and exposure to environmental antigens. In addition, research shows that filaggrin mutations vary among ethnicities, which “may explain why different ethnicities have different incidences and severity of hand eczema.”

Skin physiology differences (ie, skin barrier) among patients of various ethnicities may be associated with different sensitivities to chemicals, as with different skin pigmentations. For example, the skin of Asian individuals has a thinner stratum corneum and higher density of eccrine glands, making it more sensitive to exogenous chemicals, and darker skin tones have been shown to have lower vitamin D levels, which is a protective factor against atopic dermatitis.

For cultural practices and customs, the study authors found that disparities may stem from unique food preparations, festivals that incorporate chemicals known to increase eczema risk, or the use of homeopathic therapies (eg, topical application or consumption of herbal preparations). Utilization of essential oil extracts or aromatherapy—whether direct contact or airborne exposure—was also cited as having a high likelihood of leading to hand eczema.

Exposure risk also varies when dietary habits and associated food prep methods are considered. For example, Hispanic individuals have a greater prevalence of capsaicin hand dermatitis, which previous research has linked to the high rate of handling of various hot peppers barehanded, and pizza makers often come into contact with ammonium persulphate and diallyl disulphide. The level of nickel in certain foods, when comparing the Indian and Western diets, was also highlighted, with toxic effects of nickel ingestion including contact dermatitis.

As for climate-related disparities, the authors noted that previous research shows associations between such climatic conditions as temperature, humidity, and exposure to ultraviolet radiation and the wide range of geographical locations of ethnic groups. Further, higher latitudes and low temperatures are linked to higher rates of atopic dermatitis, but higher temperatures and low humidity may be protective factors. The findings of one study they included noted that humidity “may help to maintain ‘basal sweating responses’ and, therefore, prevent hand eczema.”

Occupations that use harsh chemicals, such as tannery work and hairdressing, have been linked to increased rates and risks of forearm and contact dermatitis, and among those who work in spice factories or handle and prepare foods, there are known elevated rates of irritant contact dermatitis and allergic contact dermatitis.

Among the socioeconomic factors that may contribute to disparities in hand eczema among various ethnicities are levels of health care utilization—especially in relation to dermatological care—language barriers, cultural reasons, economic factors, and living conditions with a higher environmental risk. In particular, children from minority groups have been linked to higher rates of mold exposure, “although other environmental exposures may have to be further examined.”

For the last area, difference in laws and regulations, the study authors wrote that regulatory differences vary by geographical location and that can influence exposure risk.

“It would be beneficial for health care professionals to be well acquainted with such factors to be better equipped to tailor the treatment approach for a patient accordingly,” the study authors concluded. “Patient awareness is vital, in particular because some cultural customs take place on a frequent or periodic basis rather than a one-time occurrence.”

Reference

Chai ESX, Tey HL, Lim ZV. Are there ethnic differences in hand eczema? a review. J Clin Med. Published online March 14, 2023. doi:10.3390/jcm12062232