DR SANDY STEELE
Seborrhoeic keratosis (SebK)
Seborrhoeic keratoses (seb K), also known as seborrhoeic warts and age barnacles, are benign (harmless) growths caused by a build-up of skin cells. They have no more malignant potential then your normal skin. Seb K are extremely common; almost everyone older than 50 has at least one, some people have many more. Seb K are uncommon under the age of 20 years.
Seborrhoeic Keratoses
What do seborrhoeic keratoses look and feel like?
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Often multiple but can be solitary. May be grouped in certain areas such as under the breasts and in the groin
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Vary in size from a few mm to several cm
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Often brown/black, but can be skin-coloured or pink
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Raised, often with a crusty/warty surface, but can be smooth or waxy to the touch
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Can feel itchy, and may be easily traumatised e.g. by catching on clothing or jewellery and bits can drop off or they may bleed. Any inflammation (redness) should settle within a few weeks
What causes seborrhoeic keratoses?
The cause is not known. Seb K are nothing to do with sebaceous (oil) glands or viral warts. They are not infectious (i.e. cannot be passed from one person to another). In people with a large number of seb K there can be a hereditary component (i.e. another family member may also have many seb K). Skin friction may be the reason they appear in body folds.
Things you can do to help yourself
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Applying a regular emollient (moisturiser) may help, particularly if a seb K is itchy
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Learn what skin cancer looks like - for more information please refer to the advice page Self-examination
Make an appointment with your Doctor:
Most seb K do NOT need treatment. Even if they grow, they have no more malignant potential then your normal skin. That being the case, they are extremely common, and so occasionally some patients can develop skin cancers within the seborrhoeic keratoses such as Intraepidermal Carcinoma (IEC of Bowens disease), especially on sunexposed skin. Always tell your doctor if a lesion abruptly changes or is tender or painful or bleeds.
Tell your doctor if:
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If one or more of the seb K catch and bleed on a persistent basis, in which case treatment may be offered
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If the lesion abruptly changes/grows, or is tender
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If you develop a skin lesion that looks different to the others i.e. an 'ugly duckling'
Seborrhoeic Keratoses
Treatment:
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Most seb K do not need treatment
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Those that catch and bleed repeatedly may be treated
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Even with treatment, seb K can grow back
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Seb K removal is not covered by medicare for cosmetic reasons
Can seborrhoeic keratoses be cured?
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Seb K usually persist, and you may develop more – you cannot prevent new ones from growing
Complications of seborrhoeic keratoses
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Seborrhoeic keratoses are not premalignant tumours. However:
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Skin cancers are sometimes difficult to tell apart from seborrhoeic keratoses.
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Skin cancer may by chance arise within or collide with a seborrhoeic keratosis.
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Very rarely, the sudden development of widespread, multiple (hundreds) seborrhoeic keratoses may be associated with underlying internal malignancy or tumour, most often gastric adenocarcinoma- talk to your GP about preventative health screening.
How is a seborrhoeic keratosis diagnosed?
The diagnosis of seborrhoeic keratosis is often easy.
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A stuck-on, well-demarcated warty plaque
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Other similar lesions
Sometimes, seborrhoeic keratosis may resemble skin cancer, such as basal cell carcinoma, squamous cell carcinoma or melanoma.
If doubt remains, a seborrhoeic keratosis may undergo partial shave or punch biopsy or diagnostic excision.
for more information:
The Australasian College of Dermatologists A-Z of skin