Midge bites are the itchy, often clustered red lumps left by biting midges, the tiny flies many Australians call sandflies. WA Health says the itch may not start for several hours, and bites can persist for days or weeks, varying a lot by person. Cover up at dawn and dusk, use repellent, and add a fan and fine mesh.
This guide is about getting your evenings back: the sunset swim, the verandah barbecue, the last golden hour on the sand. If you are still choosing a repellent for the season, start with our guide to the best insect repellent in Australia.
What are biting midges?
WA Health calls biting midges "the smallest of the blood-feeding flies," family Ceratopogonidae, measuring 1.0 mm to 3.0 mm. HealthyWA puts it simply: "tiny flies, about the size of a pin head." They are so small they "often go unobserved by the individual being bitten."
- Many species, few pests. WA Health counts over 200 species across Australia, and "only a small number cause a serious nuisance to humans."
- The sandfly name. They "are commonly, but incorrectly, referred to as sand flies." Our guide to sandflies in Australia covers the naming in full.
- Overseas. In the US they are called no-see-ums, so travelers may find our guide to no-see-um bites useful.
- Spelling. You will also see them spelt midgie or midgy.
Do midges bite?
Only the females. WA Health explains that, "as with most biting flies (including mosquitoes), only the females bite," using the blood as a protein source for their eggs. "The males feed on plant nectar only."
They rarely come alone. WA Health says biting midges "may attack exposed skin in large numbers and their bites can be irritating and painful."
What do midge bites look like?
They vary from person to person. According to WA Health:
- The bites "are usually painful and itchy."
- Some people "may experience a severe reaction with red, swollen bites measuring several centimetres in diameter."
- They "may also form blisters, become weepy and persist for days or weeks."
The detail that catches people out is timing: some people "may not be aware that they have been bitten as the itching may not commence for several hours after the bites."
Midge bite or mozzie bite?
Here is a side-by-side using only the health guidance: WA Health for midges, the US CDC for mosquitoes. For march flies, bed bugs, ticks and stings too, see our guide to insect bites in Australia.
| Midge bite (WA Health) | Mosquito bite (US CDC) | |
|---|---|---|
| Typical look | Painful, itchy bites; in strong reactors, red and swollen, several centimetres across | A puffy, reddish bump, or a hard, itchy, reddish-brown bump or multiple bumps |
| Blisters | May form blisters and become weepy | Small blisters instead of hard bumps |
| When you notice | Itching may not start for several hours | A puffy bump appears a few minutes after the bite |
| Other signs | Many bites on exposed skin | Dark spots that look like bruises |
How long do midge bites last?
The health guidance gives no exact number. WA Health says midge bites can "persist for days or weeks," and "the severity of the reaction varies from person to person." healthdirect, the Australian Government health service, says in its general insect-bite guidance that "usually, insect bites and stings will get better in a few days."
Your history with midges matters. WA Health notes that "people who are regularly exposed to biting midges may become desensitised over time," while "others, including tourists, may experience a severe reaction."
Midge bites and allergic reactions
WA Health describes the usual response as a "severe local (allergic) reaction," which "can be painful and/or irritating for some people."
The main thing to avoid is scratching: "scratching the bites can result in a secondary bacterial infection," says WA Health. healthdirect says an infected bite means "your skin will become warm, red and painful to touch," and advises: "See your doctor if your bite or sting does not get better after a few days or it looks infected."
What helps, as the health departments word it
- Cool it. WA Health suggests "an ice pack"; healthdirect suggests "a cold pack (wrapped in a cotton cloth)."
- Antihistamines. HealthyWA says "a mild antihistamine may provide some relief." healthdirect: "If you have ongoing swelling or itching, take antihistamines for up to 3 days. You can buy antihistamines at a pharmacy without a prescription."
- Keep it clean. healthdirect recommends "washing the area with soap and water," and says: "Speak with your pharmacist for advice."
- Hands off. Do not scratch.
If a bite becomes infected, WA Health says it "may require the application of antiseptic cream or the use of antibiotics. In severe cases medical advice may be required."
What the health departments actually say
Online, almost every page gives a different number of days and a different remedy. Here is what WA Health, HealthyWA and healthdirect actually say, and what their guidance leaves out.
| Question | What the guidance says | Not in the health guidance |
|---|---|---|
| What do bites look like? | Painful, itchy, may blister; red and swollen in strong reactors (WA Health) | One "signature" look for every bite |
| How long do they last? | "Days or weeks" (WA Health); insect bites usually better "in a few days" (healthdirect, general) | An exact number of days |
| Best relief? | Ice pack and antihistamine (WA Health); soap and water, wrapped cold pack (healthdirect) | Kitchen-cupboard remedies |
| Which repellent? | DEET or picaridin (WA Health) | A single "best" brand |
| Do natural repellents work? | "Generally not as effective as DEET or picaridin and may need to be applied more frequently" (WA Health) | A scent or oil that keeps midges away |
| Do they spread disease? | "Not known to transmit any human diseases in Australia" (WA Health) | Overseas or livestock stories framed as a local risk |
| Do fly screens stop them? | They "can fit through standard fly screens"; use fine mesh (WA Health) | That standard screens are enough |
| Do fans help? | Fans "may discourage midges from biting" (WA Health) | That a fan stops them completely |
| Can they live in your bed? | Eggs go in damp soil, decaying leaves and mud at the water's edge (WA Health) | Any bed or mattress breeding site |
When and where midges bite in Australia
WA Health says biting midges "are most active under calm conditions. They are most prevalent around dawn and dusk, but may continue to bite through the night and during overcast days."
They "occur in many coastal and inland areas of Western Australia," most commonly in "tropical and sub-tropical parts of the state near sandy estuarine and foreshore areas and mangrove swamps." They breed "around the edge of water bodies," in damp soil, decaying leaves and mud, and their life cycle "can take between 3 and 22 weeks."
Adult emergence "is associated with the new and full moon phases." Range varies too: "Many species will only travel a few hundred metres from their breeding sites, while others may travel several kilometres." Our sandfly guide has a planner for picking the calmest hours.
Why am I suddenly getting bitten? Can midges live in your bed?
A sudden run of bites often comes down to timing and place: a new or full moon, calm evenings, and a holiday house near an estuary or mangroves. Visitors can also react more strongly than locals.
Midges can get indoors, since they "can fit through standard fly screens." But the places WA Health lists for eggs are damp soil, leaf material and mud at the edge of water, and a bed is not on that list. Indoors, WA Health's fix is fine mesh on doors and windows, plus a ceiling fan.
How to avoid midge bites
- Mind the hours. "Avoid being outside around dawn and dusk and at other times if biting midges are active" (WA Health).
- Dress for it. "Long, loose-fitting and preferably light-coloured clothing." healthdirect agrees on long sleeves and long pants.
- Carry repellent "containing either diethyl toluamide (DEET) or picaridin," says WA Health. HealthyWA adds that "repellents will not be as effective if applied sparingly to the skin."
- Reapply after a swim, "as the product may wash off."
- Know the trade-off. "Natural or organic repellents are generally not as effective as DEET or picaridin and may need to be applied more frequently."
- Move the air. "Ceiling fans or other air circulation devices may discourage midges from biting."
- Screen it. Fine mesh on doors, windows, caravans and tents.
- Choose your spot "well away from midge breeding sites/wetlands," and "be aware of the phases of the moon."
Where plant-based PMD fits
PMD (para-menthane-3,8-diol) from lemon eucalyptus has been field-tested against biting midges. In Trigg's 1996 study, a PMD repellent and DEET each gave 98% protection against the Scottish biting midge 8 hours after application in one trial; a second trial found 99.5% for PMD and 97% for DEET at 8 to 10 hours. In California, a lemon eucalyptus repellent left half the subjects with no Leptoconops midge bites over 6 hours of exposure.
Results vary by species: a citronella and lemon eucalyptus oil product did not repel South African Culicoides in trap tests. Those studies used other formulas, not ours, and WA Health's recommendation remains DEET or picaridin.
If you prefer plant-based, our Bloc Off Spray uses 8% PMD derived from lemon eucalyptus in a water-based, alcohol-free, DEET-free formula with aloe vera and chamomile. My co-founder and formulator Cassidy Huang and I spent two years with a Taiwan-based chemist developing it. It has not been tested on midges, so apply it generously and reapply more often. The store checks out in AUD.
Your midge-season evening plan
- Sit where the air moves, away from still water and mangrove edges, with the fan on.
- Check the screens: fine mesh on the verandah, windows and tent.
- Cover ankles and necks with light, loose layers for dusk.
- Repellent on exposed skin, generously, and again after a swim. Bloc Off Wipes are individually wrapped for the beach bag or esky (more in our travel wipes guide).
- Pack an ice pack and antihistamine in the esky, just in case.
- Remember the delay. Itching may not start for several hours, so a quiet first hour does not mean you got away with it.
Then sit back and enjoy the sunset.
FAQ
What do midge bites look like?
Usually painful and itchy, says WA Health. Strong reactors may get red, swollen bites several centimetres across, and bites may blister and become weepy. Itching may not start for several hours.
How long do midge bites last?
WA Health says days or weeks, varying from person to person. healthdirect's general guidance is that most insect bites get better in a few days.
Can midges live in your bed?
WA Health lists damp soil, decaying leaves and mud at the water's edge as egg sites, not beds. They can slip through standard fly screens, so use fine mesh and a ceiling fan.
Do midges carry disease in Australia?
WA Health says biting midges "are not known to transmit any human diseases in Australia." The main issue is the itchy skin reaction.
What smell do biting midges hate?
Neither WA Health nor healthdirect names a smell that repels midges. They recommend DEET or picaridin repellent, long loose clothing, ceiling fans and fine mesh.
Written by Tanya Lee, Co-Founder of The Superbloc. Sources: WA Health, "Biting Midge (sand flies)"; HealthyWA, "Biting midges"; healthdirect, "Insect bites and stings"; US CDC, mosquito bite symptoms; Trigg 1996 and a 2006 study (22(3):483), Journal of the American Mosquito Control Association; Journal of the South African Veterinary Association.