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Linear Porokeratosis

Last updated June 2, 2018

Approved by: Maulik P. Purohit MD, MPH

Linear Porokeratosis (LP) is a subtype of porokeratosis, an uncommon skin condition that results in the manifestation of small patches of lesions of varying sizes on skin.

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

  • Congenital Facial Linear Porokeratosis
  • LP (Linear Porokeratosis)

What is Linear Porokeratosis? (Definition/Background Information)

  • Linear Porokeratosis (LP) is a subtype of porokeratosis, an uncommon skin condition that results in the manifestation of small patches of lesions of varying sizes on skin
  • Linear Porokeratosis is generally seen during early childhood including infancy. No specific predisposing factors for the condition are observed
  • The cause of development of Linear Porokeratosis is not identified yet. It may be due to certain genetic mutations that are yet to be well-characterised
  • The condition is seen as tiny red-brown skin lesions that appear in various parts of the body arranged in a linear pattern. A diagnosis of Linear Porokeratosis is made by studying the presenting symptoms and skin biopsy (microscopic examination of the skin lesions)
  • Following its diagnosis, the condition may be treated using topical creams and gels, oral medications, and laser therapy. In general, the prognosis of Linear Porokeratosis is good with appropriate treatment, since it is mostly benign

Who gets Linear Porokeratosis? (Age and Sex Distribution)

  • Most cases of Linear Porokeratosis are observed early in life - in infants and childhood
  • Both males and females are affected, although a slight female predominance is noted
  • Individuals of all racial and ethnic background can be affected

What are the Risk Factors for Linear Porokeratosis? (Predisposing Factors)

No specific risk factors for Linear Porokeratosis have been identified. However, the risk factors for porokeratosis, in general, may include:

  • Individuals with light skin are more prone to porokeratosis than dark-skinned individuals
  • Some subtypes of porokeratosis are known to run in families, which may indicate a genetic linkage
  • Exposure to ultraviolet radiation
  • Weakened immune system
  • Chemotherapy
  • Skin trauma
  • Skin infections; hepatitis C infection
  • Skin burns
  • Chronic liver failure
  • Presence of certain autoimmune disorders such as rheumatoid arthritis (RA) and psoriasis
  • Poorly-controlled diabetes
  • Long-term systemic and topical steroid therapy

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 Linear Porokeratosis? (Etiology)

The exact cause of development of Linear Porokeratosis (LP) is unknown.

  • In general, porokeratosis may be due to certain genetic factors. Presently, the specific genes causing the skin condition are under study
  • It is important to note that LP is non-contagious and it cannot be transmitted from one individual to another

What are the Signs and Symptoms of Linear Porokeratosis?

The signs and symptoms of Linear Porokeratosis (LP) include:

  • The condition manifests as multiple small reddish-brown skin lesions; mostly only small areas of the body are involved
  • They are usually present in a linear fashion on the limb or trunk; since, it is arranged in lines, it is called Linear Porokeratosis
  • Numerous skin lesions that occur in any part of the body; typically only one side of the body is affected
  • The condition usually starts in the palms and soles, but can spread to other parts of the body
  • The skin may become atrophic (skin breaks and bleed), due to the lesions

How is Linear Porokeratosis Diagnosed?

A diagnosis of Linear Porokeratosis may involve the following:

  • A thorough medical history assessment and complete physical examination
  • 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
  • Blood test to diagnose underlying autoimmune disorders, if any
  • Culture studies to rule out any infection
  • Skin biopsy: A skin 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. On examination of the specimen, certain characteristic features may be noted

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 Linear Porokeratosis?

In many cases, Linear Porokeratosis is a benign condition, and it does not cause any significant complications. However, the following factors may be a cause for concern in some individuals:

  • The presence of skin lesions may result in cosmetic issues (especially when it involves the face or exposed skin areas)
  • This may result in emotional stress
  • In some individuals, more than one subtype of porokeratosis is observed

Current studies do not indicate an increased chance of the skin lesions becoming malignant (cancerous).

How is Linear Porokeratosis Treated?

There is currently no definitive cure for Linear Porokeratosis (LP). However, the condition may require no treatment, if the symptoms are mild. In such cases, regular observation/monitor by the healthcare provider may be sufficient treatment. However, in case they are at a body site that causes discomfort and/or present significant cosmetic worries in the individual, they may be treated accordingly.

The treatment adopted for Linear Porokeratosis may include the use of the following measures:

  • Topical 5-fluorouracil medication therapy
  • Oral isotretinoin
  • Cryotherapy
  • Dermabrasion
  • Laser therapy
  • If the cause of LP is an underlying autoimmune disorder, then treatment for the same is necessary

Follow-up care with regular screening and check-ups are important and encouraged.

Note: Any medications containing isotretinoin, which is a known teratogenic agent (having the potential to cause fetal defects), should be avoided during pregnancy.

How can Linear Porokeratosis be Prevented?

Currently, there are no known methods to prevent the occurrence of Linear Porokeratosis. However, protecting oneself from the harmful ultraviolet rays of sun through the following measures (below) may avoid aggravation of the condition:

  • Use sunscreens with high sun-protection factor, wide brimmed hats, and protective clothing
  • Be aware of the hazards of prolonged sun exposure and take steps to protect yourself
  • Individuals, who are regularly exposed to the sun, or work under the sun should get their skin periodically examined by a physician
  • Avoid excessive sunbathing

What is the Prognosis of Linear Porokeratosis? (Outcomes/Resolutions)

The prognosis for Linear Porokeratosis is usually good, in a majority of cases, since it is a benign condition that may only present some cosmetic issues. Even if treatment is provided, it may not get better in many individuals.

Additional and Relevant Useful Information for Linear Porokeratosis:

  • Do not pick or pop the blisters, for doing so can affect the healing process and may result in secondary infections
  • 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
  • The presence of dirt on the body is not a causative factor for the condition. However, it helps to be clean and hygienic, which may help the condition from getting worse

What are some Useful Resources for Additional Information?

References and Information Sources used for the Article:

Helpful Peer-Reviewed Medical Articles:

Reviewed and Approved by a member of the DoveMed Editorial Board
First uploaded: June 2, 2018
Last updated: June 2, 2018