Most gnats you find indoors don’t bite. The tiny flies hovering around your houseplants or kitchen drain are almost certainly fungus gnats, which are annoying but harmless. If something in your house is actually biting you, you’re likely dealing with a different insect altogether: biting midges, commonly called no-see-ums, punkies, or sand flies. These belong to an entirely separate fly family and require different strategies to control.
What’s Actually Biting You
Biting midges are extremely small, often barely visible to the naked eye. They’re grayish-black with gray, semi-transparent wings and long legs. Unlike the fungus gnats you see circling your potted plants, biting midges don’t breed in houseplant soil. They develop outdoors in moist environments: salt marshes, mud, wet soil near standing water, and decaying organic matter like seaweed. The females bite to obtain blood for egg development, and their bites are disproportionately painful for such a tiny insect.
Fungus gnats, by contrast, are the most common gnat found inside homes. They breed in overwatered potting soil and feed on fungi and decaying organic matter. They look similar to biting midges at a glance, but they have no interest in your blood. If you’re seeing tiny flies near your plants but not getting bitten, fungus gnats are almost certainly the culprit, and you can skip straight to moisture control for your soil.
How Biting Midges Get Inside
Biting midges don’t typically breed indoors. They enter your home from outside, drawn by light, carbon dioxide, and body heat. Standard window screens have mesh openings large enough for these insects to slip through. Regular screens are designed to block mosquitoes, but no-see-ums are significantly smaller and can pass through gaps, tears, or standard-sized mesh without difficulty.
Homes near water sources, wetlands, marshes, or coastal areas are most vulnerable. Peak activity tends to happen at dawn and dusk, and midges may enter in higher numbers during warm, humid weather. If you live near any body of water or area with consistently wet soil, that’s likely where they’re coming from.
What the Bites Look and Feel Like
Biting midge bites typically appear as small, raised bumps that cluster in groups. They’re intensely itchy, often more so than mosquito bites relative to their size. The initial bite can feel like a sharp pinch or sting, followed by redness and swelling that develops over the next few hours. Most bites resolve within a few days without treatment.
For relief, apply a cold compress or ice pack wrapped in cloth for at least 20 minutes to reduce swelling. Over-the-counter antihistamines help control itching, and hydrocortisone cream reduces both itching and inflammation. Ibuprofen can help if the bites are painful. Resist scratching, as broken skin from midge bites can become infected.
Keeping Biting Midges Out
The single most effective barrier is upgrading your window screens. A mesh density of at least 20×20 per square inch (meaning 20 threads in each direction per inch) blocks both mosquitoes and no-see-ums. Some products labeled as “solar insect screens” with a 20×30 mesh density offer even better protection while also providing daytime privacy. Check all existing screens for tears or gaps, since even small openings are enough for midges to enter.
Keep windows and doors closed during dawn and dusk when midges are most active. If you need airflow, a fan directed at entry points helps, since these insects are weak fliers and struggle in moving air. Running a fan near where you sit or sleep can also reduce bites.
For personal protection, repellents containing DEET are the gold standard and work well against biting midges, black flies, and no-see-ums. Picaridin performs comparably to DEET against these species and tends to feel less oily on skin. Oil of lemon eucalyptus is the most effective natural option, offering protection similar to low-concentration DEET products. Some formulations specifically list gnats, no-see-ums, and biting midges on the label. These repellents work by blocking the sensory receptors the insects use to detect a host, rather than truly “repelling” them.
Reducing Breeding Sites Near Your Home
Since biting midges breed outdoors in wet organic matter, reducing moisture around your property limits the local population. Clean up standing water, fix leaking outdoor faucets or irrigation systems, and improve drainage in areas where water pools after rain. In coastal areas, removing decaying seaweed and organic debris that accumulates after storms eliminates prime breeding habitat.
Indoors, eliminate any unnecessary moisture sources. Fix plumbing leaks, empty drip trays under potted plants, and ensure bathrooms and kitchens are well ventilated. While these steps primarily target fungus gnats, reducing indoor humidity also makes your home less attractive to biting midges that wander in.
Dealing With Fungus Gnats at the Same Time
If you have both non-biting gnats around your plants and something biting you, you may be dealing with two separate problems. Fungus gnats are controlled almost entirely through moisture management. Allow the top layer of potting soil to dry completely between waterings. Improving your soil’s drainage by mixing in perlite or sand makes conditions less hospitable for larvae, which live in the top few inches of moist organic matter.
Most of a fungus gnat’s life is spent as a larva in the soil, so targeting the immature stages is far more effective than swatting adults. Letting soil dry out interrupts the breeding cycle. Sticky yellow traps placed near pots can catch adults and help you monitor whether the population is declining. If you’ve addressed the fungus gnats but are still getting bitten, that confirms an outdoor biting species is entering your home, and screens and repellents become your priority.