From hands to feet
A closer look at the structure of and treatments for palmoplantar dermatoses.
Eczema, psoriasis, and contact dermatitis are among the most common skin disorders. While these can occur on all regions of the body, the prevalence and severity of certain inflammatory conditions on hands and feet are especially high. The March 10 session, F089 – Hand and Foot Psoriasis, Dermatitis, and Other Inflammatory Dermatoses, tracked the difficulty of managing such incidences.
Common dermatoses, distinctive features
Skin conditions frequently develop on hands and feet in part because they are more susceptible to come into contact with irritants and allergens. For example, recent studies found that point prevalence and lifetime prevalence of hand eczema (HE) has been as high as 4% and 14.5%, respectively. Specialists also acknowledge the distinctive features that common dermatoses take on in these extremities, making diagnosis and treatment particularly challenging.
Session director Robert Bissonnette, MD, MSc, FAAD, CEO, and medical director at Innovaderm Research, shared a number of histological differences of the palms and soles compared to the rest of the body. These include:
- Thicker epidermis
- Abundant eccrine glands
- Absent hair and sebaceous glands
- Fewer melanocytes
“The first step is to make a correct diagnosis and not to hesitate to challenge a diagnosis if the morphology is atypical or if a patient does not respond to treatment,” he said.
In addition, Dr. Bissonnette said it is not uncommon for patients to present with multiple active inflammatory diseases, such as comorbid atopic and allergic contact dermatitis. He recommends patch testing in complex cases and hopes this practice will become more accessible and routine.
Where do we go from here?
Although hands and feet are easily reachable, Dr. Bissonnette said he advises dermatologists to rethink treatment plans limited to topical applications
“The problem is that penetration on palmar and plantar surfaces is limited by the absence of pilo-sebaceous units and by the thicker stratum corneum,” he said. “In addition, patients wash their hands very often, which tends to remove topical products and decrease their efficacy.”
In addition to topical options, Dr. Bissonnette said dermatologists should consider systemic and phototherapy treatments or combination therapies to sufficiently target co-existing inflammatory pathways and control dermatoses. This is based on research of disease management using skin biopsies and tape stripping.
Finally, panelists shared data from the latest studies on hand eczema, palmoplantar psoriasis, and palmoplantar pustulosis. Findings from these large, randomized controlled trials demonstrate the efficacy of certain biological and oral systemic agents.
- Topical delgocitinib has been shown effective for the treatment of chronic hand eczema.
- Dupilumab has been shown effective for the treatment of atopic chronic hand eczema.
- Risankizumab has been shown effective for the treatment of palmoplantar psoriasis.
Other speakers presenting at the session included David Eric Cohen, MD, FAAD; Emma Guttman, MD, PhD, FAAD; and Bruce Elliot Strober, MD, PhD, FAAD.
