Lichenoid keratosis

Lichen planus-like keratosis, LPLK, Benign lichenoid keratosis, BLK, Solitary lichen planus, Involuting lichenoid plaque

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Lichenoid keratosis is a small, harmless skin growth that appears as an inflamed spot or thin pigmented patch, usually showing up as a single lesion that may change color from red to purple or brown over time.

Table of contents

• What is lichenoid keratosis?
• Who gets lichenoid keratosis?
• What causes lichenoid keratosis?
• What are the symptoms and appearance?
• How is it diagnosed?
• Treatment options
• What is the outlook?

What is lichenoid keratosis?

Lichenoid keratosis is a small, harmless skin growth that typically appears as a single spot on the skin. It shows up as a small inflamed area or thin pigmented patch with a special type of tissue reaction that can be seen under a microscope.^[1]

This condition is completely benign, meaning it is not cancerous and poses no serious health risk. The growth usually appears on areas of skin that have been exposed to the sun over many years.^[3]

Lichenoid keratosis represents an inflammatory reaction, which means the body’s immune system is responding to something in the skin. In this case, the immune system appears to be reacting to an existing skin spot that is gradually disappearing.^[1]

Who gets lichenoid keratosis?

Lichenoid keratosis generally develops in people with fair skin between the ages of 30 and 80 years. It is twice as common in women compared to men.^[1]

This condition is most commonly seen in people of European descent. It rarely affects people of Asian, African American, or Hispanic backgrounds.^[1]

People who have had significant sun exposure over their lifetime are more likely to develop these growths. The condition typically affects middle-aged and older adults.^[5]

What causes lichenoid keratosis?

Lichenoid keratosis is an inflammatory reaction that arises in an existing skin spot that is gradually fading away. It most commonly occurs in pre-existing solar lentigo (a type of sun spot) or seborrheic keratosis (another harmless skin growth).^[1]

The exact reason why this inflammatory reaction starts is not fully understood. However, several triggers have been identified that may cause the reaction, including:^[1]

• Minor trauma to the skin, such as friction
• Certain medications
• Skin irritation or dermatitis
• Sun exposure

Research has shown that nearly 50 percent of people with lichenoid keratosis have the same genetic changes that are found in sun spots and seborrheic keratosis, suggesting these conditions may share a common origin.^[5]

What are the symptoms and appearance?

In most cases, lichenoid keratosis appears as a single spot on the skin. About 90 percent of people with this condition have just one lesion, though some people may develop multiple spots.^[1]

The most common locations for lichenoid keratosis are:^[1][5]

• Upper trunk (chest area)
• Upper arms and forearms
• Upper back and shoulders
• Head, face, and neck (less common)

The size of the spot can range from a few millimeters to one centimeter or more. The surface of the skin may appear smooth, scaly, or warty.^[1]

Often, lichenoid keratosis causes no symptoms at all. When symptoms do occur, they may include:^[1][5]

• Itching
• Mild stinging sensation
• Burning feeling
• Skin tightness
• Tenderness or discomfort

The appearance of lichenoid keratosis changes depending on how long it has been present. The spot may start as a light pink or red color and can change to bright purple, gray, or deep brown shades over time.^[5]

In the early stage, when the lesion has been present for about three months, it typically appears as a reddish or pinkish raised bump or patch. As time progresses to between three months and one year, the spot may become dusky-red or turn brown. In the late stage, after more than one year, the lesion may be violet-colored or show irregular shades of brown or gray.^[1]

How is it diagnosed?

Lichenoid keratosis can sometimes be mistaken for other skin conditions, including basal cell carcinoma (a common type of skin cancer). Because of this similarity, proper diagnosis is important. The condition is misdiagnosed up to 70 percent of the time.^[2]

Doctors may diagnose lichenoid keratosis through clinical examination and a special technique called dermoscopy, which uses a handheld device to examine the skin more closely. This technique reveals uniform clusters of gray dots in the affected area.^[1]

If the doctor cannot definitively diagnose the condition based on examination alone, a skin biopsy may be needed. During this procedure, a small sample of skin is removed and examined under a microscope in a laboratory. The biopsy will show a specific pattern of immune cells and tissue changes that confirm the diagnosis.^[1][3]

The microscopic examination typically shows immune cells lined up along the junction between the upper and lower layers of skin, along with other characteristic features that distinguish lichenoid keratosis from other conditions.^[3]

Treatment options

In many cases, lichenoid keratosis does not require treatment, especially if it is not causing any symptoms. If left untreated, the lesion usually clears up on its own within two years.^[2]

When treatment is desired or needed, several options are available:

Topical treatments: For cases with mild symptoms like itching, over-the-counter creams may provide relief. If these are not effective, doctors may prescribe topical corticosteroid creams to reduce inflammation and itching. In one reported case, a 2.5% hydrocortisone cream applied once daily led to successful healing.^[3]

A more recent treatment option involves the use of topical imiquimod, a medication that helps the immune system. One study reported that this treatment was effective, with no recurrence of the lesion after seven months of follow-up.^[3]

Surgical removal: Several procedures can be used to remove lichenoid keratosis, though the lesions can sometimes recur after removal. These procedures include:^[3]

• Cryosurgery (freezing the lesion)
• Electrosurgery (using electrical current)
• Curettage (scraping away the lesion)

A comparative study found that combination therapy using laser treatment along with a topical agent can be useful in managing the condition, particularly for lesions on the face.^[12]

For most people with no specific symptoms, doctors may recommend simply observing the lesion and allowing it to heal naturally over time.^[2]

What is the outlook?

The outlook for people with lichenoid keratosis is excellent. This is a completely benign condition that poses no serious health risks. The growth is not contagious and cannot spread from person to person.^[2]

Without treatment, lichenoid keratosis typically resolves on its own. The color of the lesion changes over time, varying from an initial reddish brown to a grayish purple or brown as it gradually fades away over several weeks or months.^[1]

Even though this condition is harmless, any changes in your skin should be evaluated by a healthcare provider to rule out other conditions that may look similar but require different treatment.^[5]