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White Spots on Skin from Sun: Causes, Pictures & Treatment

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Excessive sun exposure can not only lead to sunburn but also to white spots on the skin.

White spots on the skin from the sun are often idiopathic guttate hypomelanosis (also called white sun spots). However, sun exposure can also make white spots of tinea versicolor and pityriasis alba more prominent.

White spots on the skin from sun.

In this article, we will discuss three skin conditions where white spots on the skin are related to sun exposure. 

  • Idiopathic guttate hypomelanosis may be related to excessive sun exposure.
  • Tinea versicolor white spots may become more apparent after sun exposure.
  • Pityriasis alba white patches may be more prominent after sun exposure.

1. Idiopathic Guttate Hypomelanosis (White Sun Spots)

Idiopathic guttate hypomelanosis (also known as white sun spots).

Idiopathic guttate hypomelanosis can lead to white spots on the skin exposed to the sun. It’s not entirely clear why it happens but genetics and excessive sun may be the reason.

It is commonly seen in individuals with fair skin over the age of 40, and its incidence increases with age. It may be more noticeable in darker skin tones.

It presents as ill-defined round to oval hypopigmented or white spots on arms and legs, and sometimes on the face. They are usually 2 to 6 mm, although larger white patches can also occur.

In comparison to tinea versicolor, these usually have a smooth surface.

Diagnosis

These can be diagnosed by clinical examination by a doctor. In most cases, it doesn’t require more testing unless it has unusual features.

Treatment

White sun spots are harmless and do not require treatment unless for cosmetic reasons.

One can cover these areas with the use of makeup or tinted products.

Since sun exposure may be the causative factor, it is important to protect the skin from the sun by using broad-spectrum sunscreen of at least SPF 30 and sun-protective clothing. 

To get rid of these, there are several options, although the results may vary from person to person.

  • Topical steroids
  • Topical retinoids – These are vitamin A derivatives that can increase the turnover of our skin cells. In a 1999 study, tretinoin improved the sun spots when used for four months. Tretinoin is a prescription-strength retinoid. Over-the-counter retinoids like retinol (tretinoin is 20 times more potent) or adapalene may be effective but they may take a lot longer to show any visible effects. 
  • Topical calcineurin inhibitors like tacrolimus 0.1% used alone (2013 study) or in combination with fractional photo thermolysis (2016 study), may be effective.
  • Cryotherapy (where the tissue is frozen) has been found to be effective as reported in studies. In one study, it led to re-pigmentation of the area in 6-8 weeks. In another study, cryotherapy when used for 4 months led to significant improvement in the hypopigmented areas.
  • Chemical peels with agents like phenol may be beneficial. These can remove the top layer of skin.
  • Superficial dermabrasion where abrasive particles are used to remove the top layer of skin may be effective.
  • Lasers: Fractional carbon dioxide lasers and non-ablative fractional photo thermolysis via fractional1550-nm ytterbium/erbium fiber laser can lead to positive outcomes as seen in review studies. In one study, lasers were found to be more effective than tretinoin in improving these areas.

2. Tinea versicolor (Pityriasis versicolor)

Tinea versicolor.

Tinea versicolor is a fungal infection of the skin. It occurs due to the overgrowth of the fungus Malassezia. Why it happens in some people is not entirely clear, however, there are several precipitating factors:

  • Excessive sweating
  • Hot and humid weather
  • Oiliness of skin
  • Stress
  • Immunosuppression
  • Hormones 

It usually presents as spots with altered pigmentation – pink, brown, pale, or white. The surface may be dry or rough. Malassezia metabolites are thought to alter the pigment of the skin. 

These spots become more prominent after someone spends time in the sun or sun tanning, probably due to darkening or tanning of the surrounding skin.

Diagnosis

It can be diagnosed by clinical examination by a doctor. In some cases, a doctor may do tests like wood lamp examination, skin scrapings, or a skin biopsy to rule out other skin conditions.

Treatment

Tinea versicolor is usually treated with shampoos or topical creams and lotions with anti-fungal ingredients. Some of these are available over the counter like:

  • Clotrimazole (Lotrimin)
  • Miconazole (Monistat)
  • Ketoconazole (1%)

Sometimes prescription medications may be need like:

  • Topicals ciclopirox and ketoconazole (2%)
  • Oral fluconazole
  • Oral itraconazole

3. Pityriasis alba

Pityriasis alba.

Pityriasis alba is a skin condition most often seen in children and young adults. The majority of patients are under 12 years of age. The most commonly affected areas are the face, arms, neck, shoulders, and upper arms.

Pityriasis alba can present with round, oval, or irregular patches of hypopigmentation with dryness or scaliness. They may start off as pink lesions but as they heal they become pale.

They become much more prominent after exposure to the sun due to the tanning of surrounding skin. Due to this reason, the patches may become less noticeable during winter.

The exact cause of why it happens is not known. It is often seen in people who have atopic dermatitis.

It is thought to be a form of dermatitis that heals leaving behind an area of hypopigmentation. In addition, it may be associated with excess sun exposure. 

Diagnosis

It is usually diagnosed clinically by a doctor. In some cases, to rule out other skin conditions, they may do some additional tests like skin scrapings or a skin biopsy.

Treatment

This condition is harmless and usually goes away on its own. Moisturizers and emollients may be helpful.

In some cases, if the area is red, itchy, or inflamed, topical steroids like hydrocortisone may be helpful. 

Key points

White spots on the skin from the sun may appear due to different reasons. Some of these in particular are associated with sun exposure like idiopathic guttate hypomelanosis while some skin conditions become more prominent after sun exposure like white spots in tinea versicolor and pityriasis alba.

White sun spots and pityriasis alba usually do not require treatment. Tinea versicolor requires treatment with antifungals.

Sun protection can not only prevent some of the above-mentioned white spots on the skin but also protect against sunburns and skin cancer.

Further reading

References

Disclaimer: This blog post is for information purposes only and does not replace medical advice.

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