Bug bites are common and can come from bedbugs, mosquitoes, ticks, spiders, and other creatures. Many bites require nothing more than wound care at home, but others require medical attention.

A young girl in the woods scratching her leg due to a bug bite.Share on Pinterest
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Insect bites often cause an inflamed lump or spot on the skin, which may itch or change color. In lighter skin, many bug bites cause redness. In darker skin, they may cause the skin to turn purple or dark brown.

Correctly identifying the type of bug bite someone has is important for knowing how to treat it, particularly if they develop systemic symptoms after receiving the bite. These are symptoms that affect the whole body, such as a fever.

This article discusses how to identify bug bites, including those caused by bedbugs, mosquitoes, ticks, fleas, and spiders. It also explains when to seek medical help for a bite.

The human bedbug is a type of insect that relies entirely on human blood to survive. They are flat, oval-shaped insects around 3–6 millimeters (mm) long, with a red or brown color. They often live in mattresses but can also live in cushions, bed frames, and crevices in floors and walls.

Bites from bedbugs usually appear on someone’s face, neck, hands, or arms. The symptoms include small, raised bumps that occur in clusters or straight lines. The bites will be itchy but not painful.

If there are bedbugs in the home, the symptoms of the bites may take as long as 14 days to develop. Other signs of a bedbug population in the home include:

  • tiny, poppy seed-like eggs in bedding or on mattresses
  • unexplained rust colored stains on bedding
  • a sweet, musty smell

Although bedbugs do not spread disease, there is a risk as an individual may have an allergic reaction to the bites or get a secondary infection.


The treatment for bedbug bites aims to reduce itchiness. A doctor may recommend a topical steroid cream and oral antihistamines. If a secondary infection develops, this may require treatment with antibiotics.

The only way to entirely rid the home of bedbugs is to use insecticides. These chemicals are toxic, and so the Centers for Disease Control and Prevention (CDC) recommends contacting the property’s landlord or a professional pest control company to ensure safe removal.

Learn more about bedbug bites.

Mosquitoes are small flying insects that feed on blood. They have delicate wings, legs, and special feeding apparatus that allows them to bite into the skin. As a mosquito feeds, its saliva enters the skin. It is this that causes an itchy, swollen bump.

The symptoms of a mosquito bite can vary. The bite may present as:

  • a puffy bump on the skin that appears a few minutes after the bite
  • a hard, itchy red-to-brown bump that appears around a day after the bite
  • small blisters
  • dark spots that resemble bruising

In people who have more severe reactions to mosquito bites, the symptoms may include:


Treatment for mosquito bites aims to ease symptoms. People may benefit from applying ice packs, topical corticosteroids, and oral antihistamines.

Some mosquitoes can spread serious diseases. The risk for these depends on the species of mosquito and the geographical region where the bite occurs. Mosquitoes can transmit:

If a person develops any symptoms in addition to the bite, such as a fever, chills, headaches, or vomiting, they should speak with a doctor as soon as possible.

Learn about some home remedies to ease the symptoms of mosquito bites.

Ticks are arachnids that have eight legs and a pair of claws. They may have a hard or soft body and are usually flat before they feed, becoming rounder afterward.

Tick bites are often painless and do not always produce any symptoms. However, they can latch onto the skin and stay there for hours or days. As a result, the easiest way to identify a tick bite is to find the tick itself if it is still on the skin.

If the tick is no longer on the skin, there may be no signs of a bite. Some people may experience:

  • pain and swelling
  • rash
  • blisters
  • a burning sensation

Some ticks can also spread diseases, which may cause symptoms if a person contracts them. Examples of tick-borne diseases include:

If a tick bite transmits Lyme disease or RMSF, a person may develop a distinctive rash. In Lyme disease, the rash can resemble a bullseye with the tick bite at the center. Around 70–80% of people who get Lyme disease will have this rash.

In RMSF, the rash resembles pinpoint dots or splotches, but the appearance can vary widely over the course of the disease.


Treatment for tick bites depends on whether the tick is still attached to the skin. If it is, people should carefully remove the tick with tweezers, grasping them as close to the skin as possible and smoothly pulling upwards.

Removing a tick within 24 hours of the bite may reduce the chance of any disease transmission. Usually, it takes 36–48 hours before a tick transmits the bacterium that causes Lyme disease.

After the tick is out of the skin, dispose of it by placing it in a sealed bag or container, wrapping securely in sticky tape, or flushing down a toilet. Do not try to squash the tick between the fingers.

An uncomplicated bite only requires routine wound care. Clean the area with rubbing alcohol or soap and water, and monitor for signs of infection. A person may require topical steroids or antihistamines for severe itching.

If someone develops any other symptoms, they should speak with a doctor as soon as possible, mentioning that they recently had a tick bite.

If a person regularly visits areas with a high number of ticks, they should take precautions to prevent bites. Cover exposed skin wherever possible, and check the skin thoroughly for ticks before reentering the home.

Learn more about Lyme disease prevention.

Fleas are tiny insects that measure up to 4 mm long and are reddish in color. They prefer to feed on the blood of mammals and birds but may bite humans too. The bites they cause may appear as several small red bumps or blisters and can be intensely itchy.

In cases of severe itching, scratching can break the skin, allowing a secondary bacterial infection to develop. This may cause swelling, warmth, or pus to leak from the bite.

Rarely, flea bites can transmit serious diseases, including tularemia, endemic typhus, and bubonic plague.


Treatment for flea bites focuses on reducing itching until the bites heal. A doctor may suggest calamine lotion, steroid cream, or oral antihistamines.

Learn more about flea bites.

Spiders are carnivorous arachnids. Unlike ticks, to which they are related, spiders do not feed on the blood of animals or humans. Instead, they eat insects.

Many spider species have a venomous bite or sting that immobilizes their prey. If a spider is threatened or disturbed by a human, it may bite or sting them. The symptoms and severity of the bite vary widely depending on the species of spider.

Potential symptoms of a spider bite include:

  • a sharp, pinprick-like pain at the time the bite occurs
  • small puncture marks in the skin
  • red or purple discoloration at the site
  • a red or purple blister
  • pain, aching, tingling, or numbness around the bite

In North America, the two spiders with the greatest potential to cause harm are the black widow and brown recluse spiders.

Although brown recluse spider venom is potentially very dangerous, most bites cause minimal symptoms. Some may develop an area of pale or blue discoloration around the bite. A more severe complication is necrosis or tissue death.

Black widow venom does not cause necrosis, and often, the bites cause no severe reactions. If it does, a person may have severe muscle spasms and pain in the chest, lower back, and abdomen. Other symptoms include:

Severe symptoms typically happen up to 6 hours following the bites and may last up to 2 days.


Most spider bites do not cause significant symptoms. Often, people can reduce any pain at home by applying ice to the area and taking acetaminophen. In some cases, people may require a tetanus shot if they have not had one recently.

However, if someone is concerned that the spider that bit them may be dangerous, they may wish to consult a doctor.

The biggest challenge in treating spider bites is identifying the type of spider that caused it. If a person sees the spider, they should try to remember the shape, size, color, and any markings on the spider’s body. This may help a doctor diagnose and treat the bite.

People should seek immediate medical attention if they develop severe or systemic symptoms after a spider bite.

Learn more about identifying and treating spider bites.

Most insect bites are minor and do not require medical attention. However, it is important to seek immediate help if the following occur:

These symptoms can indicate anaphylaxis, which is a severe allergic reaction that can be life threatening.

Other symptoms that a person should speak with a doctor about include:

  • fever or chills
  • muscle aches
  • a bullseye rash, or a rash that keeps getting bigger
  • headaches
  • swelling and pus
  • persistent fatigue

Bug bites may look different depending on the creature that caused them, as well as a person’s skin tone, the location of the bite, and other factors.

Bedbugs and fleas typically cause small, itchy bumps to appear on the skin, whereas tick bites sometimes cause no symptoms at all. Mosquito bites tend to look puffy and raised after they first appear, while spider bites may have noticeable puncture marks.

However, it is always best to consult a doctor for a diagnosis if a person has any concerns about a bite, as they can vary in appearance and severity.