Mosquito Bite – Causes, Symptoms & Treatment

Mosquito bite

Mosquito bites are usually just a nuisance in Germany. Nevertheless, reports of severe allergic reactions have been increasing in recent times. In more southern climes, especially in South America and Africa, serious to fatal diseases can be transmitted by mosquitoes.

What is a mosquito bite?

There are numerous species of mosquitoes that can be found almost all over the world. Only the polar regions and some deserts are completely free of them. The mosquito bite is only carried out by female animals, since blood proteins are necessary for the fertilized eggs to grow.

The term “stitch” is not entirely correct on closer inspection. A mosquito has a proboscis to suck blood – it’s not a stinger. Instead, they use various mouthparts to suck blood.

Mainly the bristles are used, which have two channels inside. One injects the insect’s saliva into the skin, while the other is used to suck blood. Saliva injection serves several purposes. First, the host’s blood is prevented from clotting so that the blood meal can be sufficiently productive.

Second, chemicals are also delivered into the puncture site that first suppress the itching. After all, the “victim” shouldn’t notice anything about the sting. Subsequently, these substances lead to swelling and itching due to an intolerance reaction.


Mosquitoes are capable of transmitting diseases to humans. These include parasitic ( malaria , filariasis and leishmaniasis ), viral (including yellow fever , dengue fever ) and bacterial diseases ( tularemia ). A disease can only be transmitted if the insect has also been infected via an infected host.

The time from the ingestion of the pathogen by a mosquito and the opportunity to pass it on through the saliva is called the extrinsic incubation period. Before this time has elapsed, the infection cannot be passed on to another living being.

Symptoms, Ailments & Signs

Overall, the symptoms of a mosquito bite are very clear. A distinction must be made between the normal symptoms of any mosquito bite and the symptoms of an allergic reaction to it. So every mosquito bite can be perceived as a bite, as long as the affected person is awake.

The feeling is roughly equivalent to that of a small needle prick, but the puncture only hurts at the moment of the puncture. The puncture site is usually small and starts to itch quickly. However, there is usually no pain, just the itching . The itching can also be felt after waking up if the mosquito bite occurred while you were sleeping. The reddening of the skin from a mosquito bite is localized.

Itching and redness can be made worse by scratching. The same applies to swelling that has occurred . In the case of an allergic reaction to certain substances in the mosquito’s saliva, a more widespread skin reaction can occur. This leads to spreading redness, wheal formation, severe itching and swelling. These symptoms can vary in severity.

In severe cases, there are circulatory problems and corresponding weakness. The puncture site itself becomes particularly warm and swells enormously. A hardening – similar to a scar – usually remains after the symptoms have subsided.

Diagnosis & History

If unusual symptoms occur after a trip to tropical regions, a mosquito-borne illness should always be considered.

In the case of malaria, the incubation period can be up to 4 weeks. The symptoms of the infection, transmitted by the Anopheles mosquito, are similar to those of the flu .

Unlike yellow fever, which becomes noticeable after 3 to 6 days, malaria can often no longer be linked to the trip. Depending on the cause, the various clinical pictures are diagnosed in different ways.

Yellow fever is usually diagnosed clinically, while sand fly fever is a blood test for antibodies .

In the case of skin leishmaniasis, which is triggered by parasites of the Leishmania genus, those affected show typical skin changes in some forms. A biopsy can support the diagnosis, with boat-shaped leishmania being visible in the preparation.


Mosquito bites usually heal quickly. In rare cases, however, complications can occur. Complications are possible, among other things, due to a violent allergic reaction of the body to the proteins injected by the mosquito during the bite. As with all other insect bites, it can cause huge swelling accompanied by fever or even anaphylactic shock.However, complications arising from the behavior of the stung person are also possible. Since a severely itchy reddish wheal always develops on the affected area, attempts are often made to relieve the unbearable itching by scratching. This results in skin injuries that can serve as entry points for various bacterial pathogens.

Among other things, streptococci can get into the lymphatic system, multiply there and cause lymphedema. If the germs get into the bloodstream, potentially fatal blood poisoning (sepsis) can develop. It is also dangerous if the mosquitoes inject faecal bacteria such as coliform bacteria, which they accept by placing them on animal faecal waste, into the bloodstream when they bite.

Mosquitoes as carriers of tropical diseases do not yet play a role in Germany. However, travelers to tropical countries should also be vaccinated against tropical pathogens. Otherwise, diseases such as malaria, yellow fever, dengue fever, West Nile fever or chikungunya fever can be transmitted by a mosquito bite.

When should you go to the doctor?

Normally, a mosquito bite does not require a doctor. With sufficient cooling or the use of a mosquito ointment, which can be bought in drugstores or pharmacies without a prescription, the side effects can be alleviated. In addition, the healing process is positively supported by the use of the preparations, as they minimize the itching.

If people with a weakened immune system or infants suffer a large number of mosquito bites, a doctor should be consulted. If the side effects are so distressing that you feel very unwell, feel uneasy or crying, you need the help of a doctor. If inflammation or open wounds occur, sterile wound care is required.

If this cannot be guaranteed to a sufficient extent, a doctor should be consulted, as there is a risk of sepsis. If you have a fever, chills, sweating or pain, you should also see a doctor. There is a need for action in the event of cardiac arrhythmia, severe swelling and an increase in existing symptoms.

Treatment & Therapy

Mosquito bites from northern European areas almost never require medical attention. In some cases, allergic reactions up to anaphylaxis ( allergic shock ) can be triggered. A doctor should be consulted if any symptoms occur.

A sting without complications is treated with small home remedies, such as onion juice or a disinfecting lotion. This minimizes the likelihood of additional infection with bacteria. Despite the enormous itching, scratching is not recommended, as the symptoms can be intensified and there is a risk of inflammation. A cooling gel, which can also be used for burns and other skin irritations, provides relief against severe itching .

The more serious communicable diseases, in most cases, require urgent treatment, otherwise they can lead to death. Many therapies can only alleviate the course of the disease or strengthen the immune system to fight the infection.

No cure has yet been discovered for malaria. The drug chloroquine is taken for acute flare-ups. In the case of resistance to chloroquine and a high risk of malaria, doxycycline or atovaquone-proguanil are administered for prophylaxis. The situation is similar with yellow and dengue fever , as well as with leishmaniasis and filariasis. Tularemia, which is often fatal, is treated with antibiotics , with streptomycin being the most effective.

Filariasis, which is caused by roundworms ( nematodes ) from the filaria group, exists in numerous sub-forms, some of which are easily treatable. Mosquitoes transmit microfilariae – microscopic roundworms – through their saliva. Treatment is with anthelmintics (medicines against worms), with special medication for adult worms and microfilariae.

Outlook & Forecast

The prognosis for a conventional mosquito bite from a harmless mosquito not contaminated with pathogens is very good. A mosquito bite usually heals completely within a few days. Neither permanent skin changes nor other medical complications are to be expected. Healing ointments or suitable home remedies can be used, but are not necessary.

The prognosis is significantly worse if the puncture site has no chance to heal. This is the case, for example, when there is too much scratching or other skin disorders are present. In such cases, bacterial inflammation can rarely occur, which then leads to a local infection. Continued scratching often aggravates this condition. The prognosis for infected mosquito bites is also very good if the infection is detected early and treated quickly. In the case of local infection, healing is possible within a few days and no permanent damage is to be feared here either. The skin regenerates completely.

Bites by dangerous mosquitoes, for example in the tropics, can lead to infectious diseases that have a poorer prognosis. In the case of malaria , the mortality rate is around 20 percent if untreated, but only two percent if treated. Prompt treatment improves the prognosis. It is true, however, that mosquito bites are considered harmless in Central and Northern Europe.


The best way to prevent mosquito bites in general is to wear long-sleeved, loose-fitting clothing in problem areas. A repellent spray against mosquitoes or a mosquito net can help. With regard to the serious clinical pictures in tropical areas, information about the contagious diseases there before the trip is essential. Vaccinations are possible against many of the infections described.


Follow-up care for a mosquito bite includes, if necessary, further treatment of the itching. If this occurs again after some time, the previously tested therapeutic approaches can be used again. Creams, ointments and gels also soothe the skin and thus promote rapid healing. If the itching has completely subsided, no further follow-up measures are usually necessary.

The redness and swelling associated with the sting usually goes away on its own within a few days. However, in order to exclude possible complications in healing, this process should be observed. In this way, possible infections caused by scratching can be recognized in good time. If the swelling increases or the redness spreads, a doctor should be consulted.

With the help of a blood test, this can clarify whether the mosquito has transmitted bacteria or viruses when it bite. Special attention is also required for known allergies to insect bites. If such an allergy is present, the treatment initiated in the first step must be continued over a longer period of time after consultation with the doctor responsible. Allergic reactions can also occur at a later point in time and then require treatment as quickly as possible. Allergy sufferers should therefore observe changes in the skin condition around the bite very closely.

You can do that yourself

A mosquito bite usually does not require medical attention. The treatment can be carried out by self-executable measures. It is only advisable to consult a doctor in the event of severe allergic reactions, such as those that can occur when you come into contact with insects from tropical regions.

The first step in the treatment is cooling. This reduces the swelling and at the same time reduces the itching. Anti -itch lotions and gels can be purchased at pharmacies and drugstores. There are also special products for children with fewer additives. A tried and tested home remedy is the onion : one half placed on the stung area of ​​skin relieves itching and swelling. The pure juice of aloe vera also has a cooling effect . At the same time, it cares for irritated skin. A hot spoon on the wound also reduces the itching, since the protein in the mosquito poison is precipitated by the heat.

However, the most effective is prevention. We recommend mosquito nets on windows and doors, avoiding stagnant water, avoiding very strong perfumes and showers in the morning and evening, as the smell of sweat attracts mosquitoes. Pharmacies offer numerous sprays and lotions with mosquito repellent substances. Caution is advised when using for children and allergy sufferers. If in doubt, a doctor or pharmacist should be consulted.

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Hello! I am Lisa Newlon, and I am a medical writer and researcher with over 10 years of experience in the healthcare industry. I have a Master’s degree in Medicine, and my deep understanding of medical terminology, practices, and procedures has made me a trusted source of information in the medical world.