What are these white or brown patches?
Three ordinary conditions account for most of the questions. Panau, a yeast overgrowth. Vitiligo, an autoimmune loss of pigment cells. And the pale mark left behind after eczema or other inflammation. The first one is by far the most likely on the chest and back of a young adult in Malaysia, and it is the one with a simple treatment.
This article is for sorting them out and knowing whom to see. It is education. Panau and vitiligo are medical diagnoses, and a GP or dermatologist is the right first door for both.
What is panau (tinea versicolor)?
Panau is the Malay name for tinea versicolor, also called pityriasis versicolor. It is caused by Malassezia, a yeast that is part of the normal skin flora on nearly everyone. In heat, humidity and sweat, the yeast overgrows and interferes with normal pigmentation.
DermNet NZ describes coppery-brown, pale or pink patches with fine scale, mostly on the trunk, neck and upper arms. It most often affects young adults, is slightly more common in men, and is more common in hot, humid climates and in heavy sweaters. A systematic review in 2015 called it one of the most common superficial fungal infections worldwide, particularly in the tropics.
The yeast is already on the skin, so panau is not usually thought of as something caught from another person. What changes is the condition of the skin.
How is panau treated, and why does it come back?
Treatment is with antifungals. Medicated shampoos and washes (selenium sulfide, zinc pyrithione), antifungal creams of the azole class and terbinafine gel are the usual first line. Oral antifungals of the azole class are kept for extensive, frequent or stubborn disease. A 2022 review notes that topical treatment is preferred because it has fewer side effects and drug interactions. These are prescription or pharmacy decisions for a GP or dermatologist, and the choice depends on the extent of the patches.
Two things surprise people. The first is that it recurs. Because the yeast is a permanent resident of the skin, relapse is common, and the 2015 review found little research on how best to prevent it. DermNet NZ notes that in some places it clears in cooler months and recurs each summer. The second is that the colour lags behind the cure. DermNet NZ states that the colour, especially the pale type, may persist for weeks or months and does not mean the treatment failed. Pale patches that remain after the scale has gone are not a reason to keep applying the antifungal indefinitely.
What is vitiligo, and how does it differ?
Vitiligo is an acquired, long-term loss of pigment cells (melanocytes), caused by autoimmune destruction. DermNet NZ puts the global prevalence at 0.5 to 2%. The patches are chalk or milky white, usually smooth and without symptoms, and the common sites are the hands, face, eyelids, lips, folds and areas of repeated friction. It is not infectious, and the NHS says it cannot be caught from someone else.
The practical differences from panau are surface and site. Panau patches are slightly scaly and favour the trunk and upper arms. Vitiligo patches are smooth, often on the face or hands, and a clean, complete white. Vitiligo is also associated with other autoimmune conditions, most often thyroid disease, which is why a GP may check thyroid function.
Vitiligo needs a medical review rather than home treatment. DermNet NZ lists topical corticosteroids and calcineurin inhibitors, phototherapy and, for stable disease, surgical options. The NHS notes that treatment cannot stop the condition spreading. Pale skin without pigment burns easily and cannot tan, so sun protection matters; the sunscreen in the tropics article covers what an SPF number leaves out.
What is the pale mark left by eczema?
Eczema and other inflammation can leave pale patches after they settle. Pityriasis alba is a low-grade eczema mainly seen in children, affecting about 5% of children worldwide according to DermNet NZ, with round or oval patches of 0.5 to 5 cm, most often on the cheeks and chin, often alongside dry skin. The paler tone shows more clearly on darker skin. DermNet NZ says it clears after an average of one year, with a range of a few months up to two or three years.
A 2023 review of post-inflammatory hypopigmentation describes the same pattern for other causes: most cases resolve spontaneously over time, from months to years depending on the cause. Moisturiser and, for redness or itch, a mild steroid are the usual measures, and sunscreen reduces how prominent the patch looks because the surrounding skin tans less.
The dark counterpart is a different page. A mark that is darker than the surrounding skin after acne or a rash is post-inflammatory hyperpigmentation, covered in acne dark marks in Malaysian skin.
How do doctors tell them apart?
Mostly by looking. Colour, surface, edge, site and history carry most of the diagnosis. A doctor may add a Wood lamp, which gives panau a yellow-green glow, or a skin scraping read under the microscope, which shows the yeast. Vitiligo is usually a clinical diagnosis, supported by a Wood lamp. These are simple office tests, and they can be done before any treatment is started.
The reason to confirm first is that the three conditions need different things, and the wrong guess costs time. An antifungal does nothing for vitiligo. Waiting for a pale mark to fade when it is actually vitiligo delays a review.
The honest complication
Not every pale or brown patch is one of these three. Brown patches on the cheeks may be melasma, sun spots or Hori's naevus, set out in how to tell them apart. A single patch that is changing, growing or bleeding is a different question and needs a doctor, not an internet match. A patch that keeps spreading is also a reason to be seen.
Who to see
A GP is a reasonable first stop for a scaly patch on the trunk that looks like panau, or for new white patches. A dermatologist is the right person for vitiligo that is spreading, recurrent panau, or any patch that is unclear. Skin specialist or aesthetic doctor sets out which door suits which question.
This clinic does not claim a treatment for panau or vitiligo. Where a pale or brown mark has settled and the question is cosmetic, the pigmentation page and what a doctor checks first describe how that assessment starts, which is with the diagnosis.
Patience is part of the treatment. Pigment returns more slowly than the cause leaves.
