A seborrheic keratosis is a type of skin growth. They can be unsightly, but the growths aren’t harmful. However, in some cases a seborrheic keratosis can be difficult to distinguish from melanoma, a very serious type of skin cancer.
A seborrheic keratosis (plural: seborrheic keratoses) is usually easily identified by appearance.
Multiple lesions may appear, although at the beginning there may be just one. Growths can be found on many areas of the body, including the:
Growths are not found on the soles of the feet or the palms.
A seborrheic keratosis usually looks like a waxy or wart-like growth. It typically appears on the face, chest, shoulders or back of the body. You may develop a single growth or cluster of them. A seborrheic keratosis:
Seborrheic keratoses aren't usually painful, but they can be bothersome depending on their size and location. Be careful not to rub, scratch or pick at them. This can lead to bleeding, swelling and, in rare cases, infection.
See your doctor if:
The exact cause of seborrheic keratoses isn't known. They are very common and generally increase in number with age. The lesions aren't contagious. They tend to run in some families, so inheritance may play a role.
You can develop seborrheic keratoses at any age, but you're generally more likely to develop them if you're over age 50. You're also more likely to have them if you have a family history of the condition.
Ammonium lactate and alpha hydroxy acids have been reported to reduce the height of seborrheic keratoses. Superficial lesions can be treated by carefully applying pure trichloroacetic acid and repeating if the full thickness is not removed on the first treatment.
Topical treatment with tazarotene cream 0.1% applied twice daily for 16 weeks caused clinical improvement in seborrheic keratoses in 7 of 15 patients.
A drug that inhibits the activity of Akt kinase is currently under development and may cause seborrheic keratoses to self-destruct.
A variety of techniques may be used to treat seborrheic keratoses. They include cryotherapy with carbon dioxide (dry ice) or liquid nitrogen, electrodesiccation, electrodesiccation and curettage, curettage alone, shave biopsy or excision using a scalpel, or a laser or dermabrasion surgery. Some of these techniques destroy the lesion without providing a specimen for histopathologic diagnosis.
The shave biopsy provides histologic material for accurate diagnosis and removes the lesion in a cosmetically acceptable manner at the same time. After a shave biopsy is obtained, a curette can be employed to smooth and remove any remaining keratotic material. Generally, this is the author's preferred method of removal.
If a biopsy is not desired, light electrodesiccation facilitates a sharp curettage.
Freezing seborrheic keratoses with dry ice or liquid nitrogen avoids the need for surgical excision; however, complications of freezing include pigmentary changes and on occasion, scarring.
Curettage in conjunction with liquid nitrogen generally gives better results than liquid nitrogen alone.
Application of 70% glycolic acid for 3-5 minutes prior to curetting also is effective.
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