Actinic or solar keratosis is the name given to the white, pink or red 3-12mm scaly patches of skin that are seen on the scalp, forehead, face, back of the arms and hands of people with fair skin who have been exposed to sun for many years.

They are very common and are often felt better than they are seen. They feel like sandpaper and can prickle or itch sometimes. People often worry about them but they are harmless and are pre-malignant rather than malignant. Studies show that 0.1% of them will turn into an invasive type of skin cancer (squamous cell carcinoma) every year so it is best to have them treated.

There are several treatment options but most people choose to have them frozen with liquid nitrogen. This treatment and others are available at both clinics.

If a scaly lesion ever becomes tender, raised or bleeds, this can be a sign that it is evolving into invasive cancer and it is important to have it checked.

Bowen’s disease is another pre-malignant condition of chronically sun-damaged skin, similar to actinic keratosis. It slowly develops as a scaly, pink, well-defined patch of skin, typically on the head, neck and lower legs and can grow to several centimeters in size.

It is typically solitary whereas actinic keratoses are multiple. The risk of progression to invasive skin cancer (squamous cell carcinoma) is 3-5%, so it is best treated.

There are several treatment options for Bowen’s disease including creams, liquid nitrogen, photodynamic therapy and surgical removal.

If a scaly lesion ever becomes tender, raised or bleeds, this can be a sign that it is evolving into invasive cancer and it is important to have it checked.

Basal cell carcinoma is the most common cancer in humans. It is a tumour that can cause a lot of local tissue destruction but rarely spreads around the body, unlike melanoma. In fact, studies have shown that the chance of a basal cell carcinoma spreading is 0.001-0.28%.

There are several subtypes of basal cell carcinoma. Some are superficial and are simple to treat with creams or liquid nitrogen. Some grow as a solid mass and can be easily surgically removed. However, there are some subtypes that grow deeply into tissues and can be like an iceberg, with a small amount of tumour showing on the skin surface but a lot more tumour extending deeply underneath. Unfortunately, these aggressive subtypes often grow on the face, usually around the eyes and nose. These can be difficult to treat surgically and referral is sometimes needed to a specialist surgical unit for Mohs surgery. With Mohs surgery, the tissue is removed and examined under the microscope immediately until the entire tumour has been excised. This form of surgery is the gold standard treatment for aggressive subtypes of basal cell carcinoma on the head and neck, with very high cure rates.

Squamous cell carcinoma is the second most common type of skin cancer. They are usually found on chronically sun-exposed sites; head, neck, back of the hands, shins. They typically present as a hard, scaly, tender, raised nodule. They can grow quite quickly and become sore and bleed. 60-70% of them arise from pre-existing actinic keratoses (AKs).

They are treated with surgical excision. They rarely metastasize; rates are quoted between 0.5-5.0%, but can be higher for aggressive subtypes and tumours that regrow after excision or grow on the ear or lip.

A keratoacanthoma is a tumour that grows rapidly on sun-damaged skin. Initially, they are often thought to be a pimple and are squeezed, but have a solid core. They grow quickly to 1-2cm in size over 1-2 months, mature for a similar period, then spontaneously disappear over 3-6 months, often leaving a scar.

They can look just like a squamous cell carcinoma to the naked, eye, under the dermoscope and even under the microscope so the recommendation is that they are surgically removed. They are a controversial tumour. Some experts consider them to be a subtype of squamous cell carcinoma, others claim they are a distinct entity. There have been case reports of them spreading around the body (metastasizing) but they have a very low metastatic potential.

Melanoma is of course the skin cancer that everyone worries about and rightly so. Its incidence over the past 30 years has increased at alarming rates and New Zealand has one of the highest rates in the world. It makes up 4% of all skin cancers but is responsible for 70% of all skin cancer deaths. There are around 300 deaths from melanoma in New Zealand each year. Despite a wealth of international research into all aspects of the disease, once advanced, it remains difficult to treat and survival rates haven’t improved substantially over the years.

The best chance of cure from melanoma is to catch it early. If it is found as early ‘melanoma-in-situ’ (when the malignant cells are in the top layer of the skin or epidermis) and treated surgically, the survival rates are 100% over 5 years. You’re cured! If the melanoma reaches just 4mm deep, then the survival rate is 45% over 5 years. The take home message here is get checked if you’re worried about a mole that is changing shape, colour, size or outline or one that is itching or bleeding.

Some tips for spotting melanomas

Remember ABCD – asymmetry of shape, irregular border, multiple colours, diameter >6mm.
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Remember the ‘ugly duckling’ – a mole that just looks different from the rest.
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Keep an eye on your skin.
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Examine yourself once a month and ask your partner to keep an eye on your back and areas you can’t see.
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If you have any concerns, seek help early. Don’t wait. See your GP, skin cancer doctor or dermatologist.

To assess your risk factors to find out whether you are in a high risk group, please see either your GP, Skin Cancer Doctor or Dermatologist for a professional skin check.

Are you over 40 years old?
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Are you European?
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Do you have blonde or red hair and blue or green eyes?
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Were you born in Australia or New Zealand?
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Did you spend your youth in Australia or New Zealand?
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Did you have blistering sunburns under the age of 15 years?
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Have you been a regular user of sunbeds?
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Do you have a personal history of skin cancers (BCC, SCC or melanoma)?
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Do you have a family history of melanoma (two or more close family members)?
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Do you have sun-damaged skin (actinic keratoses, dilated veins, brown freckles)?
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Are you covered in dozens of small brown moles (benign naevi)?
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Are you covered in multiple large, dark, irregular moles (atypical or dysplastic naevi)?
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Has a mole changed, grown larger, darker, itched or bled?

To assess your risk factors to find out whether you are in a high risk group, please see either your GP, Skin Cancer Doctor or Dermatologist for a professional skin check.

Seek the shade especially betwen 10am and 4pm
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Avoid sunburn
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Avoid sunbeds
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Use broad-brimmed hats and UV-blocking sunglasses
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Use long-sleeved tops with collars
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Use SPF 15 sunscreen or higher everyday
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Keep young children out of direct sunlight to avoid sunburn
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Examine your skin regularly and seek medical advice early if you have any concerns
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See your skin doctor every year for a thorough skin examination