A new dark spot noticed after a summer of work, weekends on the water or years of everyday outdoor exposure can be easy to dismiss. But can adults develop melanoma? Yes. Melanoma can occur at any point in adult life, including in people who have never previously had a suspicious mole or skin cancer diagnosis. A changing spot deserves timely clinical assessment, not a wait-and-see approach.

Melanoma is less common than several other skin cancers, but it is the skin cancer most likely to spread to other parts of the body if it is not found early. Australia has one of the highest rates of melanoma in the world, largely because of our high UV levels, outdoor lifestyle and population skin types. The good news is that early melanoma is often highly treatable. Every minute counts when a lesion is changing or concerning.

Can adults develop melanoma at any age?

Adults can develop melanoma in their 20s, 30s, 40s and beyond. Risk generally increases with age because UV damage can build up over time, but melanoma is not only a disease of older Australians. It is also one of the more common cancers diagnosed in younger adults.

Melanoma begins when pigment-producing skin cells, called melanocytes, grow abnormally. It may develop in an existing mole, but many melanomas appear as a completely new spot on previously normal-looking skin. That distinction matters. Do not rely on the belief that a spot is harmless simply because it was not there in childhood.

It can occur on sun-exposed areas such as the back, chest, face, shoulders, arms and legs. It can also develop in less obvious locations, including the scalp, between the toes, under a nail, on the soles of the feet and in the genital area. A thorough skin check looks beyond the areas you can easily see in a mirror.

Why melanoma risk changes through adult life

There is no single explanation for why one person develops melanoma and another does not. Risk reflects a combination of UV exposure, skin type, family history and individual biology. A serious sunburn in childhood or adulthood can increase risk, particularly blistering burns. However, melanoma may also occur in people who cannot recall getting burnt.

Intermittent intense exposure is a concern. Think of long summer days at the beach after months indoors, a fishing trip, gardening, sport, working on a roof or driving a ute with one arm exposed. Cumulative exposure also matters for people who work outdoors, including tradies, farmers, landscapers, delivery workers and sports professionals.

Your risk may be higher if you have fair skin, light eyes, red or fair hair, freckles, many moles, atypical-looking moles, a weakened immune system, or a personal or family history of melanoma. Solarium use is another avoidable risk factor. There is no safe tan from a solarium.

People with darker skin can develop melanoma too. Lower natural susceptibility to UV damage does not mean zero risk, and delayed diagnosis can be more likely when people assume skin cancer cannot affect them. New or changing lesions on the palms, soles, nails and mucosal areas should be assessed, regardless of skin colour.

The changes adults should not ignore

A spot does not need to be painful, itchy or bleeding to be melanoma. In fact, early melanomas often cause no physical symptoms. What makes a lesion concerning is that it is new, changing or simply different from the other marks on your skin.

The ABCDE guide can help you notice a potentially suspicious pigmented lesion. Look for asymmetry, an irregular border, uneven colour, a diameter that is growing or larger than about 6 mm, and evolution – any change in size, shape, colour, surface or sensation. These are useful prompts, not a home diagnosis tool.

Some melanomas do not follow the familiar ABCDE pattern. Nodular melanoma, for example, may appear as a rapidly growing raised lump that is dark, pink, red, brown or skin-coloured. It can be symmetrical and may be smaller than 6 mm. A sore that will not heal, a new streak or dark patch under a nail, or a spot that bleeds without clear reason also needs assessment.

Another practical rule is the “ugly duckling” sign. If one mole or spot looks noticeably different from your others, trust that observation. You know your skin better than anyone else. Photographing a concerning spot can help you track a change, but photos must never replace an appointment with a qualified clinician.

When to book a skin check

Book a prompt skin check if you notice a new or changing mole, a dark patch that is getting larger, a lesion with several colours, or any spot that looks unlike the rest. Seek urgent medical advice if a lesion is growing quickly, bleeding, crusting, ulcerating or changing over weeks.

Do not wait for your next annual check if something is changing now. A clinician can examine the area with appropriate equipment and decide whether monitoring, imaging, biopsy or removal is needed. Only a biopsy can confirm whether a lesion is melanoma.

Routine skin-check timing is individual. People at higher risk may be advised to have regular professional checks, while others may need assessment based on a specific new concern. Your GP or skin cancer doctor can help set an appropriate schedule based on your history, number of moles, sun exposure and family risk.

If you are checking your own skin, use a full-length mirror and a hand mirror where possible. Ask a partner, family member or trusted friend to look at hard-to-see areas such as your scalp, back and the backs of your legs. This is especially helpful for people with many moles, reduced mobility or a history of skin cancer.

Prevention still matters after adulthood

Past sun exposure cannot be undone, but protecting your skin now remains worthwhile at every age. Make sun protection part of the routine, not just something reserved for beach days. In Australia, UV can be damaging even when the temperature feels mild or the sky is overcast.

Use a broad-spectrum, water-resistant SPF 50+ sunscreen as one layer of protection, applied generously and reapplied according to the label. Pair it with shade, a broad-brimmed hat, protective clothing and sunglasses. For outdoor work or sport, plan breaks in shade and keep protection in the car, work bag or sports kit so it is available when you need it.

Sunscreen is not a licence to spend longer in intense sun. It works best alongside physical protection and sensible choices about exposure. It is also worth remembering that vitamin D advice is personal. If you are worried about vitamin D, discuss it with your GP rather than deliberately exposing unprotected skin to high UV.

A skin check is about certainty, not panic

Most spots people notice will not be melanoma. But guessing at home carries a risk that is not worth taking, particularly in a country where skin cancer is so common. A professional assessment can provide reassurance when a lesion is benign and a clear pathway when it is not.

If melanoma is diagnosed, treatment depends on its type, depth and whether it has spread. Early-stage melanoma is commonly treated with surgery to remove the cancer and a margin of surrounding skin. More advanced cases may require care from a multidisciplinary specialist team. Finding melanoma before it spreads can make a profound difference to treatment options and outcomes.

Knowledge can save your life, but it is the next action that matters most. If a spot is new, changing or does not look right, make a skin-check appointment promptly. The reassurance of a clear result is valuable, and early detection gives you the strongest possible chance of simple, effective treatment.