An estimated (AD), according to Jacob P. Thyssen, MD, PhD.
“If we look at individuals with AD, the lifetime prevalence of hand eczema reaches 50%, so we see a strong association between hand eczema and AD,” Dr. Thyssen, professor of dermatology at the University of Copenhagen, said at the Revolutionizing Atopic Dermatitis symposium.
Dr. Jacob P. Thyssen
Risk factors for hand eczema – defined as eczema on the hand and/or wrists – include AD, which increases the risk by two- to threefold, as well as genetic predisposition beyond AD, exposure to irritants and allergens, female gender, young age, low socioeconomic group, high risk occupations (including construction workers and hairdressers), and tobacco smoking.
“As clinicians, we sometimes need to rule out a few differentials, including psoriasis and T-cell lymphoma. As an example, 10% of T-cell lymphoma patients, a very rare condition, have first onset of the disease on their hands,” Dr. Thyssen said. “Once we see persistent hand eczema, we need to obtain a history of irritant exposure and allergen exposure, both at home and at work, perform a patch test, sometimes a skin prick test, and ask about personal and family history of AD and psoriasis.”
He noted that while formal classification of hand eczema has been a struggle for decades, he favors the “straightforward” clinical approach from the European Environmental and Contact Dermatitis Research Group. Atopic hand eczema, he said, “is very much characterized by dorsal involvement of the hands and fingers and sparse involvement of the palmar aspects of the hands.”
The cheeks and hands are predilection sites for AD in filaggrin mutation carriers (as they are sites of low filaggrin levels), and sometimes harsh environmental exposures, such as cold and dry air. In a study of 3,335 patients in Denmark, Dr. Thyssen and colleagues found that filaggrin mutations and AD were associated with early-onset and persistent hand eczema. In another study of 3,834 adults with AD or psoriasis, he and colleagues found that among those with AD, the wrists, back of the hands, and interdigital areas were often sites of severe eczema, while palmar involvement was more uncommon.
The same findings apply for the feet in filaggrin mutation carriers with AD; the dorsal aspect of the feet was more commonly affected, compared with plantar aspects of the feet.
Medical literature regarding foot eczema is scarce, but a retrospective cohort study from Germany found that foot eczema and hand eczema often co-occur. Among 723 hand eczema patients, 201 (28%) had concomitant foot eczema. The same morphological features were found on the hands and feet in 71% of patients. Foot eczema was significantly associated with male sex, atopic hand eczema, hyperhidrosis, wearing of safety shoes/boots at work, and tobacco smoking.
In addition, a systematic review and meta-analysis of studies of hand eczema and AD found that there was a 4.29-fold increased risk of hand eczema in individuals with AD, and the risk (lifetime prevalence) of occupational hand eczema was increased by more than twofold. “However, this study could not differentiate between irritant contact dermatitis on the hands and atopic dermatitis,” Dr. Thyssen said. “The studies were not accurate enough to allow for any conclusions.”
A multicenter study of adults with hand eczema in Italy found that the proportion of patients with AD was the highest among those with severe and refractory chronic hand eczema. In addition, certain professions, including those of hairdressers, health professionals, and those in trade work, such as plumbing, were more often associated with chronic hand eczema. “This teaches us that we should be very careful about steering these patients from at-risk occupations,” Dr. Thyssen said. “Also, we should remember to treat them aggressively in the beginning to reduce the risk of severe and refractory chronic hand eczema.”
Dr. Thyssen disclosed that he is a speaker, advisory board member, and/or investigator for Asian, Arena, Almirall, AbbVie, Eli Lilly, LEO Pharma, Pfizer, Regeneron, and Sanofi Genzyme.