What Causes White Spots on Skin in a Tropical Climate?

By LIV Clinic · Medically reviewed by Dr. Narathai Vichienkalayarut, M.D. · Published November 4, 2026

Pale patches that appear after a few weeks of island sun are one of the most common skin questions we hear — and the usual cause is not the sun itself.

What causes white spots on skin in a tropical climate? The most common cause is tinea versicolor, a harmless overgrowth of yeast that normally lives on skin, which hot, humid weather and sweating encourage. The spots show up more as surrounding skin tans. Other causes include small sun-related white dots, pityriasis alba and, less often, vitiligo, so a doctor’s diagnosis matters before treatment.

The most common cause: tinea versicolor

A yeast, not dirt

The American Academy of Dermatology explains that tinea versicolor happens when a yeast that normally lives on skin overgrows, triggered by hot, humid weather, lots of sweating and oily skin. It affects people of all skin colours and is not a sign of poor hygiene.

Why it shows up on holiday

The patches stop tanning normally, so they appear whiter as the surrounding skin tans. The AAD notes that in non-tropical areas it often fades in cool, dry months — and that in tropical climates it can return easily.

Other causes of white spots

Small sun-related white dots

The Cleveland Clinic describes idiopathic guttate hypomelanosis as benign white dots, like little raindrops, on sun-exposed skin such as the arms and legs, thought to be linked to long-term sun exposure.

Pityriasis alba and vitiligo

Pityriasis alba causes slightly scaly, lighter patches, mostly in children and often linked to eczema. Vitiligo is an autoimmune condition causing smooth, milk-white patches that can spread and needs medical treatment.

Telling the common causes apart

For orientation only — several of these look alike, and only an examination confirms the cause.

How tinea versicolor is treated

Diagnosis

The AAD says dermatologists can often diagnose it by looking, sometimes using a skin scraping or a Wood’s lamp, under which affected skin can look yellowish-green.

Treatment and recovery

Antifungal shampoos, washes or creams — often with selenium sulfide, ketoconazole or pyrithione zinc — are the usual first step, with tablets reserved for widespread or recurrent cases. The yeast clears fairly easily, but skin may stay uneven for weeks or months before the colour returns.

Habits that help in hot, humid weather

Ways to reduce flare-ups while living on or visiting the islands:

• Shower soon after sweating or exercise
• Wear loose, breathable cotton or linen
• Change out of damp swimwear or gym clothes promptly
• Avoid heavy, oily body products on the chest and back
• Use sunscreen so the surrounding skin does not tan as strongly
• Ask a doctor about a preventive antifungal wash if it keeps coming back

Step-by-step: what to do if you notice white spots

A sensible sequence:

1. Note where the spots are, when they appeared and whether they itch or scale.
2. Take clear photos in daylight for comparison.
3. Avoid harsh scrubs, bleaching creams or lemon juice on the patches.
4. Use sunscreen on the area and the skin around it.
5. Book a skin assessment so the cause can be confirmed.
6. Follow the treatment plan for the full recommended course.
7. Review progress after several weeks, remembering colour can take longer to return.

When to see a doctor promptly

Changing or spreading patches

Smooth, milk-white patches that spread, patches near the eyes or lips, or any spot that is sore, bleeding or changing should be checked soon.

Recurring every hot season

If tinea versicolor returns repeatedly, a doctor can discuss preventive treatment rather than repeated self-treatment.

Skin assessment at LIV Clinic

Diagnosis before treatment

At LIV Clinic on Koh Samui and Koh Phangan, Dr. Narathai examines pale patches to confirm the cause before suggesting treatment, and refers on when a specialist is needed.

Read next

See our skin treatments, read how to fade dark marks from mosquito bites, or book a consultation.

Frequently asked questions

Safety and consultation

Any new white patch on the skin needs a proper diagnosis — several different conditions look alike, some need prescription treatment and a few need a dermatologist, so self-treating the wrong cause can delay the right care. Results vary from person to person, and no specific outcome can be promised. This article is general information, not medical advice.

At LIV Clinic, every treatment begins with an in-person assessment by Dr. Narathai Vichienkalayarut, M.D., who reviews your skin, medical history and goals before recommending a personalized plan. Book a consultation to find out whether this treatment suits you.