What a skin check actually involves

The commonest reason people put off a skin check is not fear of the result. It is not knowing what the appointment is, and a vague sense that undressing in a bright room to be examined by a stranger needs more of a reason than “it has been a while”.

It does not. Here is the whole of it.

Before you come in

Take off nail polish, on hands and feet both. Melanoma can arise under a nail and polish hides exactly the change we are looking for. Come without makeup if you can — the face is one of the highest-yield areas and foundation covers early sun damage well.

If there is a particular spot worrying you, that is the thing to say first, not last. And if you happen to have an old photograph that includes it, bring it. Whether a lesion has changed is a more useful piece of information than anything about how it looks today.

The examination

You undress to your underwear and are given a gown. The examination runs in order: scalp, face, ears, neck, torso, back, arms, hands, between the fingers, legs, feet, between the toes, and the soles. It is methodical because the dangerous ones turn up in the places nobody thinks to look — the scalp under hair, the back, the sole of a foot.

The instrument involved is a dermatoscope: a magnifier with a polarised light that cuts the surface reflection and shows the pigment network underneath. It is the difference between describing a mole and reading one. Most of what looks alarming to a patient resolves in a few seconds under it as a seborrheic keratosis or a benign naevus, and most of what turns out to matter is something the patient had not mentioned.

If something needs sampling

It is done at the same visit, under local anaesthetic, and takes a few minutes. A shave biopsy takes the top off a raised lesion. A punch biopsy takes a small cylinder. An excision takes the lesion with a margin and is closed with sutures.

You feel the injection of anaesthetic and then pressure but not pain. Afterwards the site is dressed and you go back to your day; the aftercare is on the aftercare page and the short version is keep it moist, keep it covered, and do not use an antibiotic ointment on it.

Results are discussed with you directly, and that includes when they are normal. Being told nothing and left to assume is not a result.

How often

Once a year is the usual answer for an adult with ordinary risk. More often if you have had a skin cancer, if you have many atypical moles, if there is melanoma in your family, if you are fair-skinned and burn easily, if you used tanning beds, or if you are immunosuppressed.

Current estimates put lifetime skin cancer risk at about one in five Americans. The arithmetic that matters, though, is at the other end: for melanoma found before it reaches the lymph nodes, the five-year survival rate is ninety-nine per cent. Almost all of the difference between the good and the bad version of that diagnosis is how early somebody looked.