Seborrheic keratosis
See also in: External and Internal Eye,Anogenital,Hair and ScalpAlerts and Notices
Synopsis
A lichenoid keratosis is an inflamed seborrheic keratosis that presents as a pink shiny papule or plaque with an appearance that resembles that of a nodular or cystic basal cell cancer.
Dermatosis papulosa nigra is a term given to the papular seborrheic keratoses (most often seen as dark brown 1-3 mm papules) on the face of individuals with darker skin colors.
Relatively rapid onset of numerous SKs may be a cutaneous sign of internal malignancy. Multiple eruptive SKs in association with a visceral cancer is referred to as the sign of Leser-Trélat. The most common associated malignancy is adenocarcinoma of the gastrointestinal tract.
Codes
ICD10CM:L82.1 – Other seborrheic keratosis
SNOMEDCT:
25499005 – Seborrheic keratosis
Look For
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Diagnostic Pearls
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Differential Diagnosis & Pitfalls
- Melanoma – For any dark or atypical appearing pigmented lesion, the diagnosis of melanoma should be ruled out.
- Pigmented basal cell carcinoma
- Melanocytic nevus
- Lentigo
- Bowen disease
- Bowenoid papulosis
- Verrucae
- Stucco keratosis
- Acrochordon
- Cutaneous horn
- Nevus sebaceus
- Epidermodysplasia verruciformis
- Fibroepithelioma of Pinkus
- Acrokeratosis verruciformis of Hopf
- Arsenical keratosis
Best Tests
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Management Pearls
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Therapy
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Drug Reaction Data
Below is a list of drugs with literature evidence indicating an adverse association with this diagnosis. The list is continually updated through ongoing research and new medication approvals. Click on Citations to sort by number of citations or click on Medication to sort the medications alphabetically.Subscription Required
References
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Last Reviewed:01/30/2017
Last Updated:01/24/2022
Last Updated:01/24/2022
Patient Information for Seborrheic keratosis
Overview
Seborrheic keratoses are common noncancerous (benign) growths of unknown cause seen in adults due to a thickening of an area of the top skin layer. Seborrheic keratoses may appear as if they are stuck on to the skin. They have distinct borders, and they may appear as papules (small, solid bumps) or plaques (solid, raised patches that are bigger than a thumbnail). They may be the same color as your skin, or they may be pink, light brown, darker brown, or very dark brown, or sometimes may appear black.Who’s At Risk
Seborrheic keratoses can occur any time after puberty, and almost everyone older than 50 has one or more of these skin growths. They may increase in number with age. Members of the same family can have an inherited tendency to grow multiple seborrheic keratoses. Men and women are equally as likely to develop them. People with darker skin colors tend to develop seborrheic keratoses less frequently than those with lighter skin colors.Signs & Symptoms
Seborrheic keratoses can occur anywhere on the body, except for the palms, soles, and mucous membranes (areas such as in the mouth or anus). They most commonly occur on the chest and back. Seborrheic keratoses do not go away on their own, and they do not become cancerous.They usually start as light brown or skin-colored, slightly raised areas, which can be round or oval and of varying size (usually smaller than a thumbnail, but sometimes much larger). As they grow thicker, seborrheic keratoses may become dark brown to almost black and appear to be "stuck on" to the surface of the skin. The surface may feel smooth or rough. In lighter skin colors, they may be pink or any shade of brown. In darker skin colors, they may be any shade of brown, purple, gray, or blackish.
Self-Care Guidelines
No treatment is needed unless there is irritation from clothing, such as itching or bleeding.Note that:
- There is no way to prevent new seborrheic keratoses from forming.
- Some lotions containing alpha hydroxy acids, salicylic acid, or urea may make the areas feel smoother with regular use but will not eliminate them.
- Over-the-counter freezing techniques are available but are usually not effective.
When to Seek Medical Care
If a lesion on your skin is growing, bleeding, painful, or itchy, see your dermatologist or another medical professional. Similarly, consult a medical professional for any growth that is more than one color, that is dark brown or black, or that looks different than any of your other skin growths.Seborrheic keratoses can be removed, but removal is considered a cosmetic issue and is usually not covered by insurance.
Treatments
Removal can be accomplished with freezing (cryosurgery), scraping (curettage), burning (electrocautery), lasers, or acids. The dermatologist or other medical professional might conduct a biopsy if the growth looks unusual.Seborrheic keratosis
See also in: External and Internal Eye,Anogenital,Hair and Scalp