Seborrhoeic keratosis is a very common non-cancerous skin lesion on the face, neck, shoulders, back, chest, backs of hands and front of legs. A seborrheic keratosis is a soft, well circumscribed, raised and either black, light or dark brown in colour and fortunately is benign. Seborrhoeic keratoses are more common the older you get. Some people will have many seborrhoeic keratoses and they can be quite unsightly.
They usually start to appear around the age of 40 to 50 years old. It is estimated that over 75% of people aged 70 years have seborrheic keratoses.
They are also sometimes referred to as seborrheic warts but that is not accurate as they are not contagious. They are a form of ageing benign skin overgrowth. They are usually harmless. Histologically they are termed basal cell papillomas. Note this is different from a basal cell carcinoma which is a malignant skin tumour. However, it can sometimes be difficult to distinguish a seborrheic keratosis from other lesions and a biopsy may be recommended.
It is unknown why people get seborrheic keratosis. Exposure to sunlight is a risk factor. Many people have a tendency to get them which runs in their families, then it is called a hereditary tendency.
Seborrhoeic keratoses do not transform into skin cancers.
Seborrhoeic keratosis form one of the benign skin keratosis, which also includes solar lentigo and lichen planus like lesions.
Seborrhoeic keratoses are usually oval or round-shaped and flattened plaque-like lesions as if “stuck on”. They are dry, rough-surfaced and may be scaly but are not painful. They may itch and catch on clothes, be unsightly and be of concern if they are growing. People do not like them on the face and often request that they be removed because of their appearance. They are usually slow-growing and more tend to appear with age. They can be partly pedunculated and look like small squashed pigmented skin tags.
The dermatologist will examine your skin macroscopically and by using a dermatoscope and determine the likely diagnosis. If there is any doubt about the nature of the lesion or lesions the dermatologist will biopsy your suspected solar keratosis and send the tissue to the laboratory for histopathologic analysis. If the seborrheic keratosis is troubling you or looks unsightly, then there are effective treatments available.