Palmoplantar keratodermas, also called keratosis palmaris et plantaris or PPKs, are a heterogeneous group of disorders marked by an unusual thickening of the skin on the palms of the hands and soles of the feet. It can sometimes affect the fingers and toes. The diseases are rare and usually run in families.
There are many types of palmoplantar keratoderma. Some are inherited, others are caused by outside conditions. All show themselves to some degree in the thickening of the skin on the soles and/or palms, which is called hyperkeratosis. Some also affect the fingers and toes.
Diffuse keratodermas generally affect the entire palm and/or sole and are present at birth or in the first few months of life; focal keratoderma affects mainly pressure points of the palms and soles; and punctate-type keratoderma creates small bumps or skin legions on the palms and soles. When any of these keratoderma affects the top of the hands and feet as well as the palms and soles, they are called transgradient.
Most cases of keratoderma are present at birth or appear within the first years of life. The skin on the soles or palms of the hands may be slightly whitish and later becomes red and flaky or hard and yellow in color. Oftentimes, keratodermas create walking difficulties, as the pain causes an abnormal gait. Children and adults with Palmoplantar keratodermas are more susceptible to foot odor and fungal infections like Athlete’s Foot.
Some types of keratodermas are inherited, and others are acquired through certain health conditions. The types of hereditary keratodermas include Unna-Thost, Bart-Pumphrey syndrome, Vorner’s, Mal de Meleda, Huriez Syndrome, Olmsted syndrome, Vohwinkel syndrome, PPK with sensorineural deafness, Papillion-Lefevre syndrome, Hidrotic ectodermal dysplasia, acrokeratoelastoidosis, Howell-Evans syndrome, Pachyonychia congenita, PPK striata/areata type, striate PPK with woolly hair and dilated cardiomyopathy, and hereditary painful callosities.
Non-hereditary types of keratodermas can be caused by a variety of conditions, including infections, cancer, circulation problems, medications and inflammatory skin conditions like eczema and psoriasis.
Most cases of palmoplantar keratodermas are permanent, but the thickened skin can be treated so it’s less painful and less noticeable. Common treatments include emollients, topical Vitamin D ointment, keratolytics, topical retinoids, and systemic retinoids.