Black fly bite: This is what you can do to relieve the pain

It flies noiselessly and then bites: the black fly. It is only three to four millimeters in size and looks like a harmless fly at first glance. But their bite causes swelling and severe itching.

Black flies like to crawl under the clothes of walkers. The mosquito species is particularly active in flowing water. If there is no grazing animal nearby, the bloodsuckers will also attack humans. In the case of black flies, one does not speak of a sting, but of a bite.

Blackflies: They don’t bite, they bite

The female black fly (Latin: Simuliidae) does not sting to get the blood, but rasps a small wound with its sharp mouthpart. The insect scratches soft skin areas with it until a small pool of lymphatic fluid is created. She then sucks it up and injects a protein cocktail that locally inhibits coagulation and numbs the nerves. Black flies belong to the so-called “pool suckers”.

There is nothing to fear from male blackflies. They feed exclusively on plant juices.

Symptoms: swelling and itching

The mosquito saliva and the tissue hormone histamine, which is released when the bite occurs, cause severe itching and swelling of the skin. Bruises can also develop, which can be very itchy for weeks.

Black fly bites are very painful. Unlike the bites of a mosquito, you will feel the attack of a black fly within a few minutes. A small red dot forms at the site of the bite because blood can still flow after the bite.

How to treat blackfly bites

The onset of pain and itching tempts you to scratch. But you should definitely refrain from doing this, as it means that pathogens can easily penetrate the wound from your hands.

Initial treatment can be done with your own saliva. A bit of spit has a cooling effect at first. Normal allergy medicines from the pharmacy then help against the inflammatory swelling. You can also treat the affected area with a heat pen and cortisone cream. A disinfectant also helps to reduce the risk of inflammation.

allergy and diseases

However, if the swelling is particularly large, you should have your blood tested for an allergy. In the worst case, an allergic reaction can affect the circulatory system and become life-threatening.

Painful bites, such as those of the black fly, can lead to inflammation in rare cases. Mosquito bites sometimes contain bacteria that can cause pain and fever in the human body. In these cases, treatment with antibiotics can be useful.

In Germany, however, the probability of infection is very low. In African countries, the insects can sometimes transmit river blindness. Threadworms get into the human body through the bite of the black fly and can trigger an infection that endangers the eyes and can even lead to blindness. Since blackflies live mainly near flowing water, the disease is called river blindness.

Inflammation of the lymph vessels

The bites of the black fly are not only particularly unpleasant, they also often lead to inflammation of the lymphatic vessels. This creates a red line on the skin, which used to be misinterpreted as blood poisoning, but is not nearly as dangerous.

However, if you have this symptom, you should see a doctor. This is also advisable if there is swelling, wheals or redness that goes well beyond the area of ​​the bite, especially if symptoms such as fever, chills or swollen lymph nodes are present.

How to get rid of blackflies

Agents with essential oils such as citrus or eucalyptus tend not to help against mosquitoes. Insect repellents that contain, for example, the substances diethyltoluamide (DEET) or Icaridin are better. They repel mosquitoes with their scent.

Products that contain around 30 percent DEET – a chemical insect repellent – ​​offer good protection. They work for four to five hours, after which you should apply them to the skin again. You don’t need any special protection indoors, because the black fly usually stays outdoors.

If you also want to protect yourself against mosquitoes: We have summarized the best tips for you.

Whom blackflies like to bite

Especially grazing animals such as cattle and horses that graze near water are often plagued by the black fly. One or the other animal kicks out from time to time to drive away the mosquitoes. But the black fly also bites people when there are no animals around.

However, their way of biting also has an advantage for humans: clothing with long sleeves and trousers protect against mosquitoes. This is different from mosquitoes with a proboscis. If you are outside in regions with many black flies – especially at dawn and dusk, but also during the day – it is best to cover as much skin as possible.

Black flies feel more and more comfortable in this country. So far around 50 species are known in Germany. Since they love it warm and humid, high water in early summer and flowing water offer the insects optimal conditions.

The female mosquito lays up to a thousand eggs. The larvae develop best at high temperatures and high humidity. Four generations of black flies can hatch each year. This creates particularly large populations.