Palmoplantar keratodermas (PPK)
Palmoplantar keratodermas are a group of disorders characterized by thickening of the skin on the palms of the hands and soles of the feet of affected individuals. The various forms of PPK can be divided into hereditary forms with only skin problems, hereditary syndromes with PPK as an associated feature, and acquired forms. The more commonly seen hereditary PPKs are discussed here.
Hereditary forms may be localized to the hands and feet, or they may be associated with a more generalized skin disorder. Classification of hereditary PPK is frequently confusing. A simple classification incorporates 3 factors:
1) specific form and structure and distribution of the palmoplantar keratosis,
2) presence of associated skin and other tissue (such as nails, hair, mucous membranes) disease in sites other than the palms and the soles, and
3) presence or absence of fragile or blistering skin.
Diffuse Hereditary PPK without associated features:
Diffuse Non-epidermolytic Palmoplantar Keratoderma
(also know as diffuse NEPPK, or PPK diffusa circumscripta).
Mode of inheritance: Diffuse non-epidermolytic palmoplantar keratoderma is an autosomal dominantly inherited condition traced to KRT1 and KRT16 keratins.
Onset of clinical features usually presents within the first two years of life.
Diffuse Epidermolytic Palmoplantar Keratoderma
(Also known as diffuse EPPK, Vorner disease, PPK cum degenerations granulose)
Diffuse epidermolytic PPK is the most common type of hereditary PPK. It has an autosomal dominant inheritance traced to KRT9 keratin.
Onset of clinical features usually takes place within the first year.
Clinical features are similar to diffuse non-epidermolytic PPK but the skin is fragile and may blister.
Progressive Palmoplantar Keratoderma
Progressive PPK is transmitted through an autosomal dominant inheritance.
Onset of clinical features usually appears between ages 8 and 10.
Diffuse Hereditary PPK with associated features
(Diffuse PPK is associated with extra palmoplantar skin involvement in several inherited disorders of cornification. The more common conditions are outlined below.)
Mal de Meleda
(Also know as Keratosis extremitatum hereditaria transgrediens et progrediens)
Mal de Meleda is a rare disorder seen in approximately 1 in 100,000 people. It was initially observed in inhabitants of the Adriatic island of Meleda (Miljet). It is transmitted through an autosomal recessive inheritance. Clinical features of the disorder usually appear in early infancy. Palmoplantar keratoderma is often the only manifestation.
PPK Mutilans Vohwinkel
(Also know as mutilating keratoderma, Vohwinkel syndrome, and palmoplantar keratoderma mutilans)
PPK Mutilans Vohwinkel is a rare disorder that can be transmitted through an autosomal dominant inheritance or an autosomal recessive inheritance. The genetic defect has been traced to the GJB2 gene and connexin 26. Clinical features usually appear in infancy.
Mutilating Palmoplantar keratoderma with periorificial keratotic plaques
(Also known as Olmstead Syndrome)
A rare disorder transmitted through an autosomal dominant inheritance. Clinical features usually appear within the first year of life.
Palmoplantar Keratoderma with sclerodactyly (hardening and thickening of the connective tissues of the fingers and toes).
(Also known as Huriez syndrome)
A rare disorder transmitted through an autosomal dominant inheritance. Clinical symptoms are visible in infancy.
Palmoplantar Keratoderma with peridontitis (inflammation of the gums)
(Also known as Papillon-Lefevre Syndrome)
A rare disease transmitted through an autosomal recessive inheritance. The disorder results from mutations in cathepsin C. It occurs equally among males and females. Clinical features usually appear within the first and fifth years of life.
- Topical keratolytics including 5 – 10% salicylic acid, 10% lactic acid, or 10% urea in a neutral base.
- Topical retinoids, such as tretinoin (0.05% gel and 0.1% cream), are effective, but treatment can cause irritation of the surrounding skin.
- Topical steroids can be considered, with or without keratolytics, in conditions where there is an inflammatory component.
- Treatment with 5% 5-fluorouracil has produced dramatic results in spiny keratoderma, but its use in other keratodermas has not been evaluated.
- Oral retinoids are effective, especially in some hereditary PPKs such as Mal de Meleda, Papillon-Lefevre syndrome, and erythrokeratodermia variabilis (a form of ichthyosis that often includes palmoplantar keratoderma). Most hereditary PPKs require long-term treatment. Caution is advised if the patient has a blistering form, since large erosions may occur with oral retinoids therapy. Patients should be started on a low dose, and dosage should be increased should be carefully increased to avoid flaring the disease and/or causing erosions.
- Regular foot care, careful selection of footwear, and treatment of fungal infections are important.
- Dermabrasion may help topical agents penetrate, and carbon dioxide laser treatment may be beneficial in limited keratodermas.
- For severe, difficult to treat keratoderma, surgery may need to be considered. Total excision of hyperkeratotic skin followed by grafts has been successful in a number of cases.
Adapted from eMedicine.com, Keratosis Palmaris et Plantaris. Copyright 2002, eMedicine.com, Inc.
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