Age spots (solar lentigines): what they are, causes and treatment

DermNet says solar lentigines are benign and do not require treatment unless for cosmetic reasons. The British Association of Dermatologists (BAD) notes, for the similar harmless seborrhoeic keratoses, that cosmetic treatments are not funded by the NHS and are usually obtained in the private sector.

DermNet lists the following options. It says combination-based therapy delivers the highest rates of resolution, followed by laser therapy, topical retinoids, cryotherapy and peels, and that destructive modalities carry the risk of leaving pale or dark spots, which can be temporary or permanent. Strict sun protection is required to prevent recurrence.

DermNet describes solar lentigines as flat or slightly raised, well-defined lesions found mainly on sun-exposed areas such as the back of the hands, forearms, upper body and shins. They can be round or oval, range in colour from yellow and tan to dark brown or black, and are typically uniform in colour within each spot. They vary from a few millimetres to centimetres in size and can merge together.

Unlike freckles, which fade in winter, DermNet says solar lentigo persists year-round, though it may slightly darken in summer. They are asymptomatic and do not cause itching or pain. If left untreated they will likely persist but remain benign, and can slowly enlarge or darken, remain stable, or occasionally fade.

DermNet says solar lentigines occur due to chronic exposure to ultraviolet radiation, which is thought to cause mutations that increase melanin production. They are associated with advancing age, lighter skin colour, sunburn, and the use of sunbeds and certain phototherapy. It notes several gene changes have been seen in both solar lentigo and seborrhoeic keratosis, suggesting a shared genetic basis.

They can be harder to see in darker skin types, according to DermNet. They are called liver spots, but they are caused by sun, not by the liver.

DermNet says a missed diagnosis of skin cancer, such as melanoma in situ, is a recognised complication because some lesions look similar, and that solar lentigines are an independent risk factor for melanoma. The NHS advises seeing a GP if you have a mole or mark that has changed in the ways listed below.

• A mole or spot that has changed size, shape or colour.

• A spot that is painful, itchy, inflamed, bleeding or crusty.

• A new or unusual mark that has not gone away after a few weeks, including on the palms or soles.

• A dark area under a nail that has not been caused by an injury.

• Features such as an uneven shape or edges, a mix of colours, or being larger than about 6 mm (NHS melanoma symptoms).

DermNet says solar lentigines are typically diagnosed clinically, aided by dermoscopy (a magnified view of the skin). A skin biopsy is done where there is diagnostic uncertainty or concern for malignancy, and if a lesion is variegated in colour, biopsies are taken from each distinct area.

The NHS says the GP will look at the mark and may take a photograph to send to a dermatologist (teledermatology) or refer you urgently if they think it could be cancer, which does not definitely mean you have cancer.

Several skin marks look alike in older skin. This is a general guide; only a clinician can tell them apart.

DermNet says solar lentigines can be prevented by strict sun protection. The NHS advises spending time in the shade between 11am and 3pm from March to October in the UK, never burning, covering up with suitable clothing and sunglasses, and using at least factor 30 sunscreen with at least 4-star UVA protection, re-applied frequently. It says there is no safe or healthy way to get a tan, and sunbeds also contribute to solar lentigines.

On the NHS, a GP can check a spot that worries you and refer you for a dermatology opinion if needed. Treatments for harmless spots done only for appearance are generally not funded by the NHS and are usually done privately. Choose a practitioner who will look at the spot properly before treating it, and ask for any suspicious lesion to be assessed rather than simply destroyed.