What Does It Mean When Old Mosquito Bites Still Itch?

Shannon Boyce
Reviewed by Terri Forehand RN
Itching

Mosquito bites are frustrating to deal with, as the affected area can become red, swollen, and itchy. This reaction is caused by insect saliva underneath the skin. The immune system views it as a foreign substance and immediately releases histamine. Normally the itching will last between one and five days. However, some bites take longer to heal and will continue to itch.

Possible Reasons for Continued Itching

When an older bite continues to feel itchy and irritated, it is often the result of a natural sensitivity, but these symptoms can also indicate a serious medical issue.

Your Mosquito Bite Has Become Infected

The affected area may be itchy due to an infection. When the skin is broken (this is usually caused by scratching or picking at the area) there is a higher risk that the bite will become infected. This can lead to insect bite complications like redness, swelling, increased itchiness, blisters, sores, and pus.

Cellulitis is one type of infection that can be caused by breaks or cracks in the skin. It is identified by tenderness, a warm sensation, and in many cases, itching. When a bug bite is scratched repeatedly, small openings are created. That increases the likelihood that an infection, like cellulitis, will occur. Many other infections have been linked to insect bites, including impetigo and lymphangitis.

Once a mosquito bite has become infected, it takes much longer to heal. It may also require antibiotics. According to the Seattle Children's Hospital, infected bites can be treated by:

  • Washing the sore
  • Using an antibiotic ointment
  • Covering the area
  • Repeating these steps three times a day while symptoms persist

If the infection becomes worse or the symptoms do not go away, prescribed antibiotics will likely be needed. Visit a medical professional to determine the best course of action.

It Is a Different Type of Insect Bite

It is not uncommon to be bitten by a mosquito. In fact, it happens to just about everyone. The American Mosquito Control Association states that there are over 3000 species of mosquitoes - with 176 of them in the United States alone. No wonder most people assume a swollen bite is the work of a mosquito. The reality is that many other types of bug bites appear and behave similarly. Take black flies, wasps, ticks, fire ants, and chiggers as examples. Each type of insect leaves behind itchy red marks.

The long-term symptoms of a mosquito bite tend to be quite different to other insect bites. Though the bites themselves may appear similar at first, the duration is rarely the same.

  • Black fly bites can itch for a few days or a full week.
  • Wasp stings tend to itch for two or three days but can last much longer.
  • A reaction to ticks can be as short as a few days or can last for several weeks.
  • Bites from fire ants feel itchy for three to ten days.
  • Chigger bites can take anywhere from one to three weeks to stop itching completely.

What you initially thought was a common mosquito bite may be something else entirely. Do your best to figure out what type of bug bite it is. This will help you choose the best possible treatment option. If you still feel unsure, get in touch with your doctor. They can find out what bit you and let you know whether the area is healing normally.

A Severe Allergic Reaction

Mosquito bites to the neck

Not everyone reacts to a mosquito bite the same way. For some, there are no symptoms whatsoever, and for others, they experience swelling, hives, and itching that will not go away. The latter indicates an allergic reaction. The bug bite may be red and itchy for days or even a few weeks, depending on the severity of the allergy.

One condition people with mosquito allergies can have is Skeeter Syndrome. It is an extreme reaction caused by the polypeptides in the saliva of the mosquito. While the bite may seem normal at first, a day or two later, severe symptoms will appear. They include noticeable swelling, redness, tenderness, warmth, blisters, and itchiness. This can last for a week or longer unless Skeeter Syndrome is properly treated.

To deal with an allergic reaction you need to treat it topically. Use an antibiotic ointment and take an antihistamine as necessary. (Both will help with the itching.) If the swelling and itching does not go away or lessen after a week, consult a doctor. Stronger antibiotics may be required.

The Bite Has Turned Into Dermatofibroma

In rare cases, a bite can turn into something more. Dermatofibroma is a small non-cancerous growth on the skin. It typically occurs when skin trauma has occurred, like an insect bite, for example. While this condition is generally cosmetic, pain and itchiness can occur. That means your old mosquito bite has the potential to become a long-term problem.

To determine whether your bite has turned into dermatofibroma, consult your dermatologist. He or she will examine the area and discuss your options. For some, dermatofibroma does not cause excessive skin irritation and removal is not a necessity. However, if tenderness and itching persist, further action must be taken.

A dermatologist will either remove the growth through surgery or by using liquid nitrogen. While it might not be a pleasant experience, that old mosquito bite can finally stop itching.

When to Speak to a Professional

Most mosquito bites are nothing to worry about, but there are times when it is necessary to contact a medical professional. Continued itching may indicate a more serious issue. Since there are many health issues linked to mosquitoes, such as malaria, West Nile, and the Zika virus, it is a good idea to take extra precautions.

If you are concerned about any symptoms or how long the bite is taking to heal, book an appointment with your doctor. They can determine the best course of action for your specific needs.

It's important to note that the most serious side effect from a mosquito bite other than the discomfort from itching and superficial infection can include a change in mental status, fever, and flu like symptoms. If you experience any alteration in mental status or fever, seek emergency medical care right away.

Old Mosquito Bites Can Be Treated

There are many possible reasons for an older bite to itch. Once you have determined the cause, you can begin the most appropriate method of treatment.

What Does It Mean When Old Mosquito Bites Still Itch?