Sun safety – South Africa has some of the strongest UV on earth

South Africa sits at a high altitude over much of its interior, close to the summer sun's overhead position, and under a part of the atmosphere with historically thinned ozone. The result is ultraviolet radiation at levels that would be considered extreme almost anywhere in the northern hemisphere, for months at a time.

South Africa has one of the highest rates of skin cancer in the world. Most of the damage that causes it is accumulated in ordinary daily life — walking, commuting, working outdoors, watching sport — rather than on a beach.

1. 1Shade and timing. Between roughly 10:00 and 15:00 the UV is at its strongest; staying out of direct sun then does more than anything else on this list.
2. 2Clothing. A closely woven shirt with sleeves blocks UV completely and never wears off or gets missed.
3. 3A wide-brimmed hat. A cap leaves the ears, neck and sides of the face exposed, and those are common sites for skin cancer.
4. 4Sunglasses with UV protection. UV damages the eyes and contributes to cataracts and to cancers of the eyelid.
5. 5Sunscreen, last — because it is the easiest of these to apply too thinly, forget to reapply, or rely on instead of the four above.

More melanin does give real protection against sunburn and against the most common skin cancers. It does not remove the risk, and it changes the pattern in a way that costs lives.

Skin cancer in people with darker skin is more often found in places the sun rarely reaches — the soles of the feet, the palms, under a nail, inside the mouth. Because neither patients nor clinicians expect it there, it tends to be found late, when it is far harder to treat. Any new, changing or non-healing mark in those places needs to be looked at.

Everyone, of every skin tone, is also at risk of eye damage, of premature skin ageing, and of photosensitivity reactions from medication.

Several common medicines make skin burn much faster than usual — sometimes after minutes rather than hours. This catches people out because they have never burned that easily before.

If a leaflet mentions photosensitivity, take it seriously: cover up, and do not rely on sunscreen alone. Ask a pharmacist if you are unsure whether something on your list is affected.

• A mole that changes in size, shape or colour, or that has an uneven edge or more than one colour.
• A mole that is itchy, bleeds, or looks different from all your others.
• A sore or scab that does not heal within a few weeks.
• A new lump, particularly pearly, shiny or with visible small blood vessels.
• Any dark streak under a fingernail or toenail that you did not injure.
• A new or changing mark on the sole of the foot or the palm.