Mosquito bite symptoms

Learn to differentiate between the common symptoms of a mosquito bite and the more serious reactions

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Health Advisor
Ask Felicity

16 August 2016

Mosquito bites

The name ‘mosquito’ comes from the Spanish word ‘little fly’ but you should not be fooled by their appearance. Mosquitoes are small but lethal insects that usually inhabit warm, tropical countries and are infamous for their capacity to spread deadly and dangerous diseases.

This is because female mosquitoes need to ingest blood in order to be able to reproduce properly. This makes them particularly fond of any warm-blooded human that stumbles into their midst and they usually attach themselves to any visible skin, draining your blood through a sharp, elongated mouthpiece known as a proboscis, and injecting their saliva into your bloodstream.

A mosquito only needs to be attaching to your skin for six seconds in order to produce a reaction from your immune system1.  In most cases, despite their reputation for carrying disease, the most irritating symptoms will normally occur because of this immune reaction as your body will recognise the proteins in the mosquito saliva as being dangerous. This will then cause a number of symptoms to manifest around the bite mark itself, usually in the form of skin lesions, swelling and itching.

If you want to read more about the appearance of a mosquito bite, then please check out our blog, ‘What does a mosquito bite look like?’


Common mosquito bite symptoms

As we have mentioned, not all mosquito bites foreshadow deadly diseases like malaria or yellow fever. Often the main source of aggravation is the proteins contained in mosquito saliva. These proteins can sometimes prevent your blood from clotting and prompt an inflammatory response from your immune system, triggering many of the common mosquito bite symptoms.

  • Discolouration: When you are bitten by a mosquito, it will trigger a response from your immune system. The immune system recognises the toxins in mosquito saliva as being harmful and releases a wave of inflammatory chemicals to counterattack the invading pathogens. These chemicals can sometimes stimulate the melanocytes, the cells responsible for producing the dark skin pigment melanin, causing small dark spots to appear around the affected area, possibly resembling bruising. Inflammatory chemicals like histamine also dilate your blood vessels, inspiring skin redness around the bite mark.
  • Lumps: When a mosquito bites you, your body will react within minutes. The primary symptom of a mosquito bite is often the pale, swollen lump that appears around the bite mark itself. This inflamed pustule is normally characterised by a small red dot in the centre of the affected area. Over a period of days, this lump can harden, with multiple puffy lesions appearing, depending on how many times you have been bitten
  • Inflammation: Inflammation is usually one of the first visible symptoms of a mosquito bite. In response to mosquito saliva entering your bloodstream, the immune system will try to protect your body and destroy the harmful pathogens. In order to do this, inflammatory chemicals like histamine are directed to the affected area, causing your skin to redden and swell in an effort to remove the irritants and begin the healing process
  • Itching: Itching can be one of the more aggravating symptoms of a mosquito bite. It’s a natural reaction to inflammation and skin irritation but it can often upset your sleep and leave you vulnerable to contracting a secondary bacterial infection. This is because when you continuously scratch your skin, you are weakening the epidermal layer, disrupting the healing process and destroying healthy skin cells, making it easier for other pathogens and allergens to penetrate your skin.

Moderate mosquito bite symptoms

If you have a weakened immune system, then sometimes more moderate symptoms can present themselves. Children, for example, are more prone to developing these symptoms because their immune systems are not fully formed or able to build a resistance against the chemicals contained in mosquito saliva. This can cause a more intense allergic reaction, leading to more unpleasant symptoms developing.

However, if you have any doubts about any of the symptoms that you are experiencing, you should always speak to your doctor just to confirm that what you are experiencing is normal and not a precursor to a more serious medical illness.

  • Blistering: Blistering is a more serious skin reaction to a mosquito bite, often appearing in those with a weakened immune system. Small, fluid filled pustules will start to appear around the bite mark, sometimes causing irritation and pain. However, you should resist the urge to squeeze or pop any blisters as, similarly to scratching, it can slow down the healing process, weaken the skin and make you more susceptible to contracting a secondary bacterial infection
  • Hives: Hives are a common appearance in those that suffer from ‘skeeter syndrome’ or have a weakened immune system, hives are itchy red welts that can occur as a result of an allergic reaction, either to food, pollen or insect bites. They are normally extremely irritating but not known to have any long term effects, usually diminishing within six weeks or so of manifesting
  • Swollen lymph nodes: Occasionally, when your body has a more extreme reaction to a mosquito bite, your lymph nodes or glands can become swollen and inflamed. This is mainly due to the role that your lymph glands play in helping the immune system to fight infections and pathogens. In rare instances, swollen lymph glands can be a sign of a mosquito-borne illness like Dengue fever, but more often than not the symptom is found in children that have been bitten by a mosquito and usually it fades as the bite is treated or diminished
  • Mild headaches: Having a mild headache is considered a moderate reaction to a mosquito bite, normally appearing in those who have a weakened immune system. You can experience slight pain or tension, but it is not usually persistent and can be relieved used conventional painkillers or home solutions. If your headache intensifies or is prolonged, it might be a sign of a more serious illness and you should consult your doctor as soon as possible
  • Low fever: A mild or low fever is a symptom that can sometimes occur, normally when the immune system is struggling to fight off an invasive pathogen. You might find that your temperature is slightly, but not alarmingly, higher than usual. This symptom should begin to diminish within a few days but if it persists or worsens, you should speak to your doctor immediately as it might be a sign of a more serious, mosquito-borne illness.

Serious mosquito bite symptoms

While moderate mosquito bite symptoms are often a sign of a weakened immune system, serious mosquito symptoms like vomiting, diarrhoea and joint pain can indicate that you have contracted a mosquito-borne disease like malaria, zika or yellow fever.

If your condition is diagnosed quickly, it can be treated successfully with proper medication, however if you allow your symptoms to linger, you might be putting your health and your life at risk.

  • Anaphylaxis: A dangerous and potentially life-threatening condition, anaphylaxis usually appears in intense allergic reactions and can be characterised by dizziness, wheeziness and difficulty breathing. Your immune system causes the blood vessels to swell abnormally, trigger anaphylactic shock within minutes of coming into contact with the perceived pathogen. If you are not treated quickly enough, it can be fatal
  • Severe headache: A severe headache is classified as a persistent headache that causes potent amounts of pain. It can be sometimes be a symptom of mosquito-borne afflictions like as Zika or West Nile disease, so you should speak to your doctor just to confirm that you are not suffering from one of these conditions
  • High fever: If your temperature is raised over 37oC you are considered to have a high temperature. If you become feverish, your temperature is normally over 38oC and if it continues to climb higher, you can be at serious risk. Fever is associated with many different mosquito inhibited diseases, like malaria and yellow fever. If you are in doubt, speak to your doctor as soon as possible to achieve a diagnosis and start any relevant treatment
  • Skin rash: A skin rash can occur as a symptom of chikungunya virus, a mosquito-borne disease that can affect your muscles and joints. Although skin reactions like inflammation and discolouration are commonplace after being bitten, if a rash continues to develop and shows no signs of diminishing, you should speak to your doctor just to clarify that what you are experiencing is normal and non-threatening
  • Fatigue: If you are unused to hot, tropical climates then sometimes the increased temperatures and heat can make you feel lethargic, meaning that any symptoms of fatigue often gets overlooked by holidaymakers abroad. However, fatigue can be a warning sign of dangerous afflictions like West Nile Virus or chikungunya virus. If you notice that you feel abnormally tired after being bitten, then it might be worth visiting your doctor just to make sure that what you are feeling is not a precursor to a more serious condition
  • Nausea: Feelings of nausea, like fatigue, can often be overlooked or misdiagnosed, either as food poisoning or heatstroke. If you’ve been bitten by a mosquito though, you should be aware that nausea is often a sign of diseases like chikungunya virus and should not be ignored. If you manage to catch this illness is its early stages, you might be able to avoid some of the other unpleasant symptoms that can manifest alongside nausea
  • Vomiting: Vomiting is never a good sign and should always be treated seriously. In cases of a mosquito bite, the affliction can precede more serious symptoms and even be an indicator that you are suffering from dangerous illnesses, such as malaria, dengue fever or yellow fever
  • Diarrhoea:Diarrhoea can be unpleasant and embarrassing to experience but if you are on holiday, the chances are you would blame the affliction on food poisoning, dirty water or another ailment. However, if you’ve been bitten by a mosquito you should consider the idea that you might have contracted a more unfortunate disease. If you are unsure, you should visit your doctor just to put your mind at ease and confirm whether it is just an upset stomach or something more serious
  • Joint pain:Joint pain can be debilitating and is not a symptom that you might immediately associate with a mosquito bite. However, it is a leading side-effect of chikungunya virus and if left untreated it can even become chronic, lingering for months, if not years, after other symptoms have diminished. If you are uncertain about your joint pain, you should speak to your doctor
  • Disorientation: If you are feeling disorientated, you might be tempted to blame heatstroke or dehydration. If you’ve been bitten by a mosquito though, it can herald an assortment of mosquito-borne viruses. Drink plenty of fluids and speak to a doctor so that you can determine exactly what is causing your confusion.

What should I do if I’ve been bitten?

If you have been bitten by a mosquito, even if you are just suffering from mild, superficial symptoms, you need to speak to a doctor. Mosquito bites are often a mild complaint but sometimes they can be deadly and you don’t want to take any chances with your health.

If you are unsure about how to protect yourself from the little beasts, you can check out my ‘Top 10 tips to prevent mosquito bites’ for more information or try using our Neem Insect Repellent Spray, which does not contain DEET. Instead, this spray utilises extracts of neem, making it a gentler option for sensitive skin without compromising on efficiency. 

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