Infected Mosquito Bite Symptoms and Treatment

An infected mosquito bite often has an extended area of redness and warmth around it. It may also have red streaks spreading outward from the bite.

The best way to prevent an infected mosquito bite is to relieve the itching. When you scratch it, it could cause an infection by breaking the skin and allowing bacteria to get in. If the infection is left untreated, it could turn into a more serious infection, such as cellulitis.

This article discusses infected mosquito bites. It explains the signs of an infected mosquito bite, how to treat it, and when to see your healthcare provider.

Symptoms of an Infected Mosquito Bite

A mosquito bite is an itchy bump that occurs after a mosquito feeds on your blood.

The itchy bite is technically an allergic reaction to proteins in the mosquito's saliva. Nearly everyone is allergic to mosquito bites to some degree. While a small segment of the population has no reaction, a small percentage can experience severe allergic reactions (anaphylaxis).

Itching and redness from a mosquito bite typically last no longer than four days, though the bump may last up to a week. If symptoms of a bug bite worsen after the first 24 hours or persist longer than four days, it could be infected.

A mosquito bite can become infected when scratched. If the skin breaks, bacteria can enter the skin. Signs of an infected mosquito bite include:

• Feeling hot to the touch
• Significant redness
• Swelling

If left untreated, infected bug bites can develop into an abscess or a more serious infection known as cellulitis.

Symptoms of an Abscessed Mosquito Bite

An abscess is an infected pocket of pus just under the skin. A mosquito bite can become abscessed if bacteria gets into the bite. Signs of an abscessed mosquito bite include:

• Drainage of fluid or pus
• Hardened skin tissue and swelling around the infection
• Redness, tenderness, and warmth in the area
• Skin lesion that may be an open or closed sore or a raised area

In some cases, an abscess can cause body-wide symptoms including fever and chills. If you have signs of an abscessed bug bite, see your healthcare provider.

Signs of Cellulitis From a Bug Bite

Cellulitis is a serious bacterial infection of the skin that can occur if a mosquito bite becomes infected. Symptoms of cellulitis include:

• Redness or red streaking that spreads from around the bug bite to cover a wider area of skin
• Tissue swelling extending beyond the immediate area of the bite
• Painful skin
• Pitted appearance of skin, similar to an orange peel
• Skin may also blister and peel

If left untreated, cellulitis can spread and cause serious health problems. If you have symptoms of cellulitis, see your healthcare provider. 

How Can I Treat an Infected Mosquito Bite?

If you suspect a mosquito bite is infected, you'll want to see a healthcare provider for treatment. Before you go, you can clean the area with soap and water. You can use calamine lotion and ice to relieve symptoms.

You should also draw a ring around the outer border of the affected area so you can tell if it spreads. If the redness and swelling begins to extend beyond the line, contact your healthcare provider.

Infected mosquito bites are often treated with oral antibiotics. More serious infections may require IV antibiotics.

If you develop an abscessed mosquito bite, applying a warm compress can ease the pain and help it drain. Your healthcare provider may need to drain the abscess to remove the infection.

How to Stop the Itch

Treating the itch can help prevent mosquito bite infections. Here's how to relieve bug bite symptoms:

• Avoid scratching: Scratching provides only temporary relief and scratching too much can result in breaking the skin. Once you break the skin, you may start bleeding and run the risk of infection.
• Use lotion: There are a few over-the-counter anti-itch lotions that might help alleviate the itching of the common mosquito bite. The most effective lotions contain one or more of these ingredients: calamine, diphenhydramine (Benadryl), or hydrocortisone.
• Cold compresses: Ice packs may help alleviate itching. Cold constricts blood vessels, blocking blood flow to and from the bite. Whenever using ice for an injury, keep it on for only 15 minutes, and don't put ice or bags containing it directly on the skin. Icing the skin too long can result in frostbite.
• Oral antihistamines: If you feel itchy after mosquito bites or you have a lot of bites, you might try oral antihistamines containing loratadine, cetirizine, or fexofenadine.
  

When to See Your Healthcare Provider

If you've been bitten by a mosquito and you develop the following signs of infection, see a doctor:

• Blistering or peeling skin extending from the bite
• Fever with or without chills
• Fluid or pus draining from the area
• Hardened skin around the bite
• Painful skin
• Red streaking extending from a bug bite
• Red and swollen skin beyond the immediate areas of the bite
• Skin appears pitted, similar to an orange peel
• Skin feels warm and tender to the touch
  
• Tissue swelling extends beyond the immediate area of the bite
  

Preventing Mosquito Bites

In the case of mosquitoes, an ounce of prevention really is worth a pound of cure. But since mosquitoes are more common in warmer seasons when you want to spend time outdoors, there are some precautions you can take:

• Consider timing. Mosquitoes are most active—and most likely to bite—during sunrise and sunset. If possible, avoid being out at those times.
• Use repellents. There are several types of mosquito repellents available on the market—including natural options—but DEET has been shown to be the most effective at keeping mosquitoes and other biting insects at bay.
• Wear proper clothing. Long sleeves and spraying your clothing with repellent can be very effective protection, but note, permethrin is a repellent made for clothing that should never be applied directly to the skin.
• Get rid of standing water. Mosquitoes breed in stagnant water, so getting rid of any buckets, puddles, or untreated pools will help cut down on mosquitoes in your area.
• Install or fix your window screens. Mesh screens allow air to come in but keep bugs out.
• Clean up potential breeding areas. Mosquitoes that hatch in the neighbor's yard are just as likely to bite you as they are to bite them. A neighborhood cleanup project in early spring can help get rid of standing water and mosquito breeding grounds.

A Word From Verywell

In most cases, mosquito bites are usually just a nuisance. They sting badly and cause intense itching, discomfort, and restlessness but do not cause major health problems. However, in certain situations, diseases can be transmitted by mosquitoes. Common preventative measures that you can use to protect yourself from mosquito bites include using insect repellent, wearing protective clothing, avoiding activities in mosquito-attracting areas, using a mosquito net, and avoiding perfumes.

— KASHIF J. PIRACHA, MD, MEDICAL EXPERT BOARD