Sandfly and No-See-Um Bites in Arugam Bay: Why They're So Itchy and How to Stop Them

Every week or two, someone walks in scratching at a cluster of small red bumps around their ankles, ask us “what bit me?”, and are surprised when the answer isn’t a mosquito. If the bites appeared after a sunset stroll on the sand, or after sitting out for a beer as the light went gold, the culprit is almost always a sandfly — sometimes called a no-see-um, biting midge, or “beach fly” depending on who you ask. They’re a genuine nuisance in Arugam Bay, and they earn their reputation.

What’s actually biting you

Sandflies here are tiny biting midges, barely a millimetre or two long — small enough to pass through most standard mosquito netting and easy to miss even when they’re landing on you. Unlike mosquitoes, which you can often hear or feel coming, sandflies bite silently and usually in numbers, which is why you tend to end up with a cluster of bites rather than one or two.

They’re most active at dawn and dusk, and especially in the still air of early evening — exactly the hours travelers are relaxing on the beach, at a beachfront restaurant, or walking back from a surf session as the sun goes down. Calm, humid evenings with little wind are prime sandfly conditions. They breed in damp sand, decaying vegetation, and the wet margins around lagoons and river mouths, so areas near the lagoon and any beach with washed-up seaweed tend to have more of them than open, breezy stretches of sand.

Why the bites itch so much

Sandfly saliva contains compounds that trigger a stronger allergic and inflammatory response in most people than a typical mosquito bite does. The bite itself is often barely felt, but the reaction that follows can be dramatic: a small hard, intensely itchy bump appears within hours, sometimes with a tiny blister or a halo of redness around it. Bites are frequently clustered — a line or group of bumps around the ankles, lower legs, or waistline, wherever clothing was loose or skin was exposed.

The itch tends to peak a day or two after the bite and can last a week or more, which surprises people who expect it to fade like a mosquito bite does. Scratching makes it worse and raises the risk of the next problem.

The real danger: infection from scratching

Sandfly bites themselves are not dangerous for the overwhelming majority of travelers. The problem we see far more often than the bite itself is a scratched, broken bite that gets infected in the heat and humidity here. Fingernails carry bacteria, tropical skin doesn’t dry out and scab cleanly the way it might at home, and repeated scratching keeps reopening the same small wound.

Signs the bite has become infected rather than just irritated:

• Increasing redness spreading outward from the bump, rather than staying the same small size
• Warmth, swelling, or tenderness that gets worse instead of better after a few days
• Pus or cloudy fluid, rather than clear fluid, from a scratched bite
• A fever, or feeling generally unwell alongside the skin changes

If you notice any of these, come in. A short course of antibiotics or an antiseptic cream clears this up quickly, but it’s much easier to treat early than after it’s spread.

Treating an ordinary bite

• Wash the area with soap and water as soon as you notice bites, especially if you’ve been on the sand.
• Use an antihistamine cream or tablet. Both help, and an oral antihistamine at night can take the edge off the itch enough to actually sleep.
• A cold compress for ten minutes at a time reduces swelling and takes the itch down a notch.
• Calamine lotion or a mild hydrocortisone cream works well on the individual bumps if the itch is intense.
• Keep nails short and consider covering bad clusters with a light dressing overnight, mainly to stop unconscious scratching while you sleep.
• Avoid scratching, obviously easier said than done — but this is genuinely the difference between a bite that fades in a few days and one that turns into a skin infection needing antibiotics.

Most people don’t need to see anyone for ordinary sandfly bites. Come in if the itching is unbearable, if you’re covered in dozens of bites and reacting more strongly than usual, or if you see any of the infection signs above.

Prevention

Sandflies are genuinely harder to keep off than mosquitoes, mostly because they’re small enough to get through gaps that would stop a mosquito. A few things do make a real difference:

• DEET or picaridin repellent, applied to ankles, lower legs, and any exposed skin before sunset walks or evening beach time. Standard mosquito repellents work on sandflies too.
• Cover up in the evening. Long, loose trousers and closed shoes for a sunset walk beat sandals and bare ankles, which is where most people get bitten.
• Avoid sitting directly on the sand at dusk, especially near damp patches, seaweed, or the lagoon edge. A raised chair or mat helps.
• Fine-mesh netting is more effective than standard mosquito netting if you’re sleeping somewhere open-air, since sandflies can pass through wider mesh.
• A fan on in the room helps — like mosquitoes, sandflies are weak fliers and don’t do well in moving air.

A note for surfers

Dawn patrol and the evening session both put you on the beach exactly when sandflies are most active, and wetsuit boots or bare ankles below a wetsuit are a favourite target. If you’re prone to strong reactions, apply repellent to ankles and feet before you walk down, not just before dinner, and rinse and dry off properly afterward rather than sitting around in a damp wetsuit at dusk.

Related reading

• Mosquito Bite Prevention in Sri Lanka: A Practical Guide
• Allergic Reactions in Sri Lanka: Recognising a Reaction That Needs Treatment
• Fungal Skin Infections in Arugam Bay: Prevention and Treatment

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This article is general health information and not a substitute for medical advice. If a bite looks infected or the itching becomes unbearable, come in and see us, or call 1990 for emergency transport.