White spots on skin: What are those pale freckles you get on your arms during summer?

Small white spots on the skin is a condition known as idiopathic guttate hypomelanosis. [Photo: Getty]
Small white spots on the skin is a condition known as idiopathic guttate hypomelanosis. [Photo: Getty]

With August and summer holiday season in full swing, you may be experiencing some unanticipated side effects – from the undesirable (like heat rash) to the unknown perks of extra sun, like better sleep.

But there’s one side effect we’re not so sure about, and that’s the strange white spots we see appearing on our arms.

Slightly larger than freckles, they are lighter than the surrounding skin and more obvious when skin is sun-kissed.

READ MORE: SPF, UVB and UVA explained

So, what actually are they? And should we be concerned about them?

What are white skin spots?

The white spots, otherwise known as sun spots, are a condition known as idiopathic guttate hypomelanosis (or IGH for short).

Dr Stefanie Williams, dermatologist and medical director of EUDELO Dermatology & Skin Wellbeing, breaks down the long, complicated name, explaining: “Hypomelanosis means lighter in colour than the surrounding skin, guttate means resembling tear-drops in shape, and idiopathic means in general that a condition arises spontaneously and that there is essentially no known cause.”

She adds: “Idiopathic hypomelanosis guttate are flat, usually smooth smooth and 2 to 5 mm in diameter.

“They are harmless and non-symptomatic.

“Non-symptomatic means they not causing any symptoms such as pain or itchiness – which means you can only see them, but not feel them, and you wouldn’t know they are there if you closed your eyes.”

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According to dermatology nurse Emma Coleman, the condition is “most often found on the shins and sun-exposed parts of the forearms [but] also may arise on other sun-exposed areas including the face, neck and shoulders.”

How do you get IGH?

As with regular freckles, you’re more likely to get IGH if you have a genetic predisposition. ICH is more common in people with light-coloured skin, and can affect men and women. However, women over the age of 40 are the group most commonly affected.

Although dermatologists do not have a definitive answer as to the cause, it is thought to be down to a combination of ageing and sun damage, according to Coleman.

“It is thought to be an inevitable part of the ageing process, with a gradual reduction in melanocytes – a similar process to hair greying,” she says.

“Other theories include sun damage - where the lesions are a kind of white freckle - or non-sun related seborrhoeic keratoses.”

Is IGH dangerous?

ICH is not thought to be dangerous.

Coleman says: “IGH does not appear to be due to injury, trauma or infection, and there is no evidence to suggest that the white areas lead to skin cancer.”

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However, as it is linked to sun damage, it is important to note the importance of adequate sun protection in order to prevent skin cancer – which has soared 45% in the UK in the past decade.

Can you IGH be treated?

As previously mentioned, wearing the right SPF for your skin type will limit the effects of sun exposure.

“It’s hard to avoid them, if you have a genetic predisposition to get them, but regular SPF30-50 and avoidance of excessive sun exposure is certainly recommended and may lower the risk of developing these,” says Williams.

Options include using a group topical treatments known as calcineurin inhibitors, which help to reduce skin inflammation.

Williams also suggests topical vitamin A to improve the appearance of white spots – “but they generally don’t require treatment”.

There are also laser treatments available, according to Healthline.