Australia has the highest melanoma rate in the world. Most Australians know at least a little about melanoma. It’s a potentially deadly skin cancer which is linked to sun exposure. A melanoma develops in the skin cells which produce melanin, the pigment that gives our skin colour. It arises in moles and as the cancer grows the appearance of the mole changes. When looking for melanoma a dermatologist or general practitioner will look for a mole which has grown, changed appearance or colour, is an irregular shape and is larger than 6mm. Many people know to watch out for these skin changes and to see their doctor if they notice any of these signs.Most Australians don’t know that there are multiple types of melanoma. One of the least common is also one of the most deadly. Acral lentiginous melanoma or ALM is rare, accounting for only 1-3% of melanoma diagnoses in Australia. Unfortunately, if you’re diagnosed with ALM you are twice as likely to die within 5 years as if you were diagnosed with the most common type of melanoma, cutaneous malignant melanoma. Much of this increased risk is due to people not recognising the signs or even doctors being unaware of what those signs are.ALM is unusual in that it usually grows on the palms of the hands, soles of the feet or beneath nails. As ALM usually looks very different to the most common types of melanoma it can be diagnosed at a later stage. The colour and size of the skin lesion will change, but instead of becoming a dark, large or unusually shaped mole it may have a number of different appearances. An ALM can be a flat, pale, red or even blue tinged lesion. It can be a raised or bumpy lesion which looks like an ulcer or weeps when bumped. It can even be a dark spot under a nail or a dark streak growing within a nail.As well as the appearance being unusual, ALM affects a different group of people to other melanomas. With most melanomas, the highest risk group is Caucasians, especially those who are very fair or have blond or red hair. ALM affects all races at about the same rate. This means that while it doesn’t occur more often in people whose ethnic background is from Asia or Africa, it is the most common type of melanoma in these groups. Unfortunately, they are less likely to have regular skin checks and doctors can be less likely to check for skin cancer in these groups. This means that ALM is often diagnosed at a later stage than other types of melanoma, which may be part of the reason why it is so much more deadly.Given how variable the appearance can be it’s important to see your dermatologist if you notice any changes like this on your hands or feet. If you do develop an ALM your prognosis will be much better if it is diagnosed sooner than later. It’s also a good idea to ensure that your doctor checks your hands, feet and nails during a skin check, especially if you are not fair skinned.