Many different types of insects (bugs) can bite you. Most insect bites itch, but the bites themselves aren't serious. The main problem with insect bites is that:
Insect bites can spread serious diseases like malaria Malaria read more and Zika virus Zika Virus Infection Zika virus infection almost never makes children or adults very sick. But Zika virus is very dangerous to an unborn baby (fetus). Zika can be spread by mosquitoes, sex, or blood transfusion... read more
Common biting insects in the United States are:
Flies, including sand, horse, deer, black, and stable flies
Mosquitoes
Fleas
Lice
Bedbugs
Kissing bugs
Some water bugs
None of these insects has venom (poison).
Ticks Tick Bites There are several different types of ticks in the United States. Tick bites themselves aren't serious. The main problem with tick bites is the spread of serious diseases: Deer ticks spread Lyme... read more 
, spiders Spider Bites Almost all spiders are venomous. However, the fangs of most species are too short or too fragile to penetrate human skin. Although at least 60 species in the United States have been implicated... read more 
, and mites belong to a different group and aren't insects.
What are the symptoms of an insect bite?
Most bites result in:
A small, red, itchy bump
Sometimes, you might have:
A large sore (ulcer) that is swollen and painful
Symptoms of infection, such as redness and swelling around the bite
Very rarely, symptoms of an allergic reaction, such as a rash, hives, or trouble breathing
Fleas can sometimes cause an allergic reaction even if you're not bitten.
What diseases are spread by insect bites?
Different types of insects spread different diseases. Not every insect carries disease, even in areas where many insects do.
Some of the diseases spread through insect bites are:
How are insect bites treated?
If you think you're having an allergic reaction, go to the hospital right away. If you know you're allergic, you should always carry epinephrine (medicine to treat a serious allergic reaction) with you. You inject the epinephrine into your own skin through a thin needle, or someone does it for you.
Doctors will tell you to:
Clean the bite
Apply a medicated cream to the bite to lessen your pain, itching, and swelling
Take an antihistamine medicine (such as diphenhydramine) if you have many bites
