'Fungal acne' is the everyday name for Malassezia folliculitis, where a yeast that normally lives on skin overgrows in hair follicles and causes small, itchy, same-sized bumps, usually on the chest, back, shoulders and hairline. It isn't true acne and usually needs antifungal care guided by a doctor, so see your GP if you think you have it.
Malassezia is a yeast that lives on almost everyone's skin and feeds on the oils in sebum. When conditions suit it, it can overgrow inside hair follicles and set off inflammation, which shows up as small, itchy bumps rather than the blackheads and whiteheads of ordinary acne [1][2][5].
Heat, humidity and sweat are the biggest triggers. In one study 83% of people with it worked in a warm environment and 71% said sweating made it worse, and a Brisbane dermatologist notes that people in humid climates are more prone to it [2][7]. Heavy or occlusive products such as rich moisturisers, some sunscreens and body oils, plus tight clothing, can trap sweat and oil around follicles [1][3][6].
Antibiotics can tip the balance. They reduce the skin's usual bacteria and let the yeast take over, which is why some people get worse on acne antibiotics; in one study 65% had previously been misdiagnosed and given antibiotics for acne [2][5]. A weakened immune system or steroid medicines also raise the risk [1].
It is most common in teenage boys and young men with oily skin, but women get it too, and it often turns up alongside ordinary acne. In clinic studies from Thailand, Turkey and Korea, about one in four people being treated for acne also had it [1][2][4].
When to see a doctor
Your bumps are itchy and look all the same size, with no blackheads or whiteheads [1][4].Acne products or acne antibiotics haven't helped, or things got worse on antibiotics [2][3].The bumps are spreading on your chest, back, shoulders, upper arms or hairline.They keep coming back, especially in hot, humid weather or after workouts [2].You're unsure what it is, or you have a weakened immune system or take steroid medicines [1].Start with your GP, who can look at it and may take a quick skin scraping to check under a microscope; you can ask for a dermatologist referral if it is hard to pin down or keeps returning [1][6].Ask a pharmacist before using a dandruff shampoo on your face or body. Antifungal tablets for this need a prescription; the fluconazole capsule sold by pharmacists is only for vaginal thrush [17].
You can't be sure on your own. Clues include itch, lots of small bumps that look the same, no blackheads, and spots on the chest, back, shoulders or hairline that don't respond to acne products. In one study, itchy patients were about seven times more likely to have it [4]. Many people have both at once, so a GP check, sometimes with a skin scraping, is the way to know [1][3].
General information only, not medical advice.