What are the other Names for this Condition? (Also known as/Synonyms)

• Brunauer-Fohs-Siemens Syndrome
• Palmoplantar Keratoderma, Striate type
• Striate PPK

What is Striate Palmoplantar Keratoderma? (Definition/Background Information)

• Striate Palmoplantar Keratoderma is a form of hereditary focal palmoplantar keratoderma that is transmitted in an autosomal dominant manner. The condition manifests during early childhood. Hereditary focal palmoplantar keratoderma is a type of palmoplantar keratoderma (PPK) caused by genetic mutations
• PPK is a benign skin condition, wherein there is thickening of skin (keratoderma) of the palms and/or soles. PPK is considered to be a pattern of skin findings and not a condition in itself. The abnormal skin thickening can be focal (localized), widespread (diffused), or punctate type (appearing as tiny bumps)
• Striate Palmoplantar Keratoderma presents thickening of outer skin layer or epidermis of the palms (including the fingers) and soles, with localized plaques on the plantar aspect of feet (sole of the feet). Striate PPK is described as a simple and focal PPK that does not cause damage to the epidermal layer (termed nonepidermolytic). Involvement of other organs are also not noted in this genetic skin condition
• A diagnosis of Striate Palmoplantar Keratoderma can be made by clinical (skin) exam and various other diagnostic tools including dermoscopy and wood’s lamp examination. The treatment involves the use of moisturizers, topical creams, and skin softeners. The prognosis of Striate PPK is determined on a case-by-case basis, but is generally better than that of diffused forms of hereditary keratodermas

Who gets Striate Palmoplantar Keratoderma? (Age and Sex Distribution)

• Striate Palmoplantar Keratoderma is a congenital disorder; the early signs and symptoms are noted in very young children
• The condition affects both males and females
• It is seen worldwide, and all racial and ethnic groups may be affected

What are the Risk Factors for Striate Palmoplantar Keratoderma? (Predisposing Factors)

• The risk factor for Striate Palmoplantar Keratoderma includes a positive family history of the condition
• Children born to consanguineous partners or spouses have a higher risk for the condition

In rare cases, Striate PPK may show an association with the following conditions/disorders:

• Acral malignant melanoma
• Brachymetacarpia and brachyphalangia
• Hypotrichosis, acroosteolysis, and periodontitis
• Left ventricular dilated cardiomyopathy and woolly hair
• Pili torti, hypohidrosis, hypodontia, and hypoacusis

It is important to note that having a risk factor does not mean that one will get the condition. A risk factor increases one’s chances of getting a condition compared to an individual without the risk factors. Some risk factors are more important than others.

Also, not having a risk factor does not mean that an individual will not get the condition. It is always important to discuss the effect of risk factors with your healthcare provider.

What are the Causes of Striate Palmoplantar Keratoderma? (Etiology)

Striate Palmoplantar Keratoderma is caused by genetic abnormalities which are passed down (through families) in an autosomal dominant pattern. It is classified into the following three types based on the involved gene:

• Mutations in desmoglein 1 gene is termed Type I Striate PPK
• Mutations in desmoplakin gene is termed Type II Striate PPK
• Mutations in keratin 1 gene is termed Type III Striate PPK

The genetic abnormalities cause decreased production of related proteins from structural disruptions in the gene, leading to the appearance of characteristic signs and symptoms.

Autosomal dominant: Autosomal dominant conditions are traits or disorders that are present when only one copy of the mutation is inherited on a non-sex chromosome. In these types of conditions, the individual has one normal copy and one mutant copy of the gene. The abnormal gene dominates, masking the effects of the correctly functioning gene. If an individual has an autosomal dominant condition, the chance of passing the abnormal gene on to their offspring is 50%. Children, who do not inherit the abnormal gene, will not develop the condition, or pass it on to their offspring.

What are the Signs and Symptoms of Striate Palmoplantar Keratoderma?

In general, the signs and symptoms associated with Striate Palmoplantar Keratoderma may include:

• The presence of small patches of abnormally-thickened skin on the palms of the hands and soles of the feet in children
• These skin thickenings are mostly the “striate” type i.e., they are present as thick lines
• The skin thickening involves some portions of the palm and sole (localised presentation); the soles are affected more than the palms
• On the soles, the thickened areas are noted on the pressure points, such as on the toe mounds and heel
• Linear thickened skin plaques may form as the condition progresses
• In some individuals, it may occur in patches (areata); they may also be mixed striate type
• It is often aggravated by physical activity (use of hands and fingers)
• Rarely, the skin lesions may also develop on the elbows and knees
• In Type I Striate PPK, plantar pain and excessive sweating (hyperhidrosis) is noted
• Type III Striate PPK may show diffuse thickening on soles
• Since, the skin thickening is localised to an area and may be small, it may resemble corns on the feet
• There is an absence of transgrediens (i.e., contiguous extension of skin thickening beyond the palms and soles)
• The condition may be painful in some individuals, particularly keratoderma on the feet
• Normal activities that involve the use of one’s hands and feet may be severely affected

No other body organs or systems are typically affected in Striate PPK. A variant of Striate PPK, called hereditary painful callosities, involves only the feet.

How is Striate Palmoplantar Keratoderma Diagnosed?

The diagnosis of Striate Palmoplantar Keratoderma may involve:

• A complete evaluation of medical history along with a thorough examination of the skin lesions by a dermatologist
• The healthcare provider may also ask many questions related to the individual’s age, family medical history, current medications, cosmetics, body lotions used, other medical conditions, infections, etc.
• Blood tests that may include complete blood count (CBC) test, basic metabolic panel, and liver function test (LFT)
• Dermoscopy: It is a diagnostic tool where a dermatologist examines the skin using a special magnified lens
• Wood’s lamp examination: In this procedure, the healthcare provider examines the skin using ultraviolet light. It is performed to examine the change in skin pigmentation
• Molecular genetic testing to identify the gene involved
• Skin biopsy: A skin tissue biopsy is performed and sent to a laboratory for a pathological examination. The pathologist examines the biopsy under a microscope. After putting together clinical findings, special studies on tissues (if needed) and with microscope findings, the pathologist arrives at a definitive diagnosis

Many clinical conditions may have similar signs and symptoms. Your healthcare provider may perform additional tests to rule out other clinical conditions to arrive at a definitive diagnosis.

What are the possible Complications of Striate Palmoplantar Keratoderma?

The complications associated with Striate Palmoplantar Keratoderma may include:

• Emotional stress
• Cosmetic concerns
• Disruption of normal life and activities if the condition is severe
• Lack of treatment response

How is Striate Palmoplantar Keratoderma Treated?

There is no cure for Striate Palmoplantar Keratoderma, and the condition is managed through symptomatic treatment (skin softening treatments) that may involve the following measures:

• Use of moisturizing creams and lotions; use of ointments containing vitamin D
• Use of oral and systemic retinoids
• Administration of keratolytics (medicine containing salicylic acid or lactic acid)
• Phototherapy
• Surgical debridement (removal of thickened skin)

Regular follow up visits with the healthcare provider is important and recommended.

How can Striate Palmoplantar Keratoderma be Prevented?

Currently, Striate Palmoplantar Keratoderma is a genetic disorder that cannot be prevented. However, the following may be considered:

• Genetic testing of the expecting parents (and related family members) and prenatal diagnosis (molecular testing of the fetus during pregnancy) may help in understanding the risks better during pregnancy
• If there is a family history of the condition, then genetic counseling will help assess risks before planning for a child
• Active research is currently being performed to explore the possibilities for treatment and prevention of inherited genetic disorders such as hereditary palmoplantar keratoderma

What is the Prognosis of Striate Palmoplantar Keratoderma? (Outcomes/Resolutions)

The prognosis of Striate Palmoplantar Keratoderma may vary from one individual to another and is dependent on the severity of the condition.

• In many individuals, the symptoms are known to improve with age. Also, the limbs and digits are not severely affected to the point of being amputated (no spontaneous amputation noted)
• However, Striate PPK is a longstanding condition; the treatments may not be very effective in some cases

Additional and Relevant Useful Information for Striate Palmoplantar Keratoderma:

Cleaning the skin too hard with strong chemicals or soaps may aggravate the skin condition. Care must be taken avoid strong soaps and chemicals that could potentially worsen the condition.