Spider Bites Symptoms and Treatment 

Seeing a spider in your home is a common occurrence for most people. But are these spiders anything to worry about? Although all spiders are capable of biting, few can actually pierce the human skin.¹ These bites are also accidental most of the time.

In the United Kingdom, there are around 650 types of spiders, but only around two per cent are capable of biting humans.2 When a spider does bite, it may be painful. But these bites are usually harmless, and very few cases should be a concern that requires medical advice.² However, bites from certain types of spiders and other animals may be harmful. Therefore, it is always important to recognise bites from spiders so that they can be treated appropriately.

This article explores how to identify a spider bite, the common symptoms that you may experience, and how to manage these bites. Knowing what you are dealing with when you or someone else experiences a bite will help you to make an informed decision when seeking treatment.  

Common spider bite symptoms

Localised symptoms

Bites from spiders are similar to regular insect bites.¹ The main symptoms include:³

• A small bite mark 
• Redness and swelling,
• Itching or pain at the bite. Replace with at the bite site.

Severe symptoms

It is always important to monitor your symptoms after you first notice a bite. When a harmful spider, such as a black widow, bites, symptoms are usually much more serious and require medical attention.¹ These include:⁴

• Muscle pain or cramp
• Nausea and vomiting
• Headache
• Sweating
• Chills
• Fever
• Difficulty in breathing

Types of spider

Spiders are generally categorised into venomous and non-venomous. A venomous spider is one that can bite and inject its toxins into you. Whilst some venomous spiders can be deadly, it is worth noting that not all of them will cause you harm. These dangerous spiders are also extremely rare in places such as the United Kingdom. 

Common venomous spiders

Black widow spider

Black widow spiders are probably the most well-known venomous spiders. They are found throughout the world, including the United States.⁵ They can be found indoors but are mostly in undisturbed outdoor spaces. 

Key features of black widow spiders:

• Shiny black body 
• A red hourglass pattern underneath the abdomen.^5,6 
• Length  approximately 2 cm (or 1.5 inches)

A black widow bite typically produces:⁶

• Two puncture marks
• Pain at the bite site can spread throughout the body
• Nausea
• Difficulty in breathing 

Brown recluse spider

The brown recluse spiders is reported as one of deadliest in the United States.⁵ It is also referred to as the violin spider due to the dark violin-like patterns on its head.⁶ Similarly to the black widow spiders, brown recluse spiders are usually found outdoors.⁶ 

Key features of brown recluse spider include:

• Distinctive violin pattern
• Length  approximately 0.7 cm (or 0.25 inches)

The brown recluse spider will rarely bite unless it feels threatened.⁶ But when this does happen, the bite will usually feature:⁶

• A small white blister
• Stinging with or without pain at the bite site

False widow spider

The false widow is the most venomous spider found in the United Kingdom. However, unlike the similarly named black widow, false widow spiders are not harmful.⁷ There are many types of false widow spiders found throughout the United Kingdom, but the most common is the noble false widow.⁷ They are often found in and around homes.⁸ 

Key features of the noble false widow include:

• Skull-shaped markings 
• Length usually 0.7 to 1.4 cm (or 0.28 to 0.55 inches)

The bite from a false widow usually:⁷

• It is small in size
• Produces pain around the bite site that lasts between 12 and 24 hours

Non-venomous spiders

These spiders are generally harmless to humans and are more of a nuisance than a threat.⁹ The following spiders are those that you will likely see in and around your home. But they are not able to bite humans, so try not to worry if they appear in your home. 

Common house spider

The common house spider is unsurprisingly found most commonly indoors.⁹ They are also most often found in homes during the autumn months.⁹

Key features of a common house spider:⁹

• Brown body
• Variable length up to 12 cm (or 5 inches)

Daddy long legs, spider

Many of us will be very familiar with the Daddy long legs spider.¹⁰ These spiders are typically found indoors as they like warm, stable temperatures, which makes our homes unfortunately very appealing.10 Unlike the common house spider, the daddy's long legs are seen at all times of the year.¹⁰ 

Key features of a Daddy long legs spider¹⁰ are:

• Very small grey-brown body
• Long thin legs 
• Length of up to 4.5 cm (or 1.7 inches)

Missing sector orb web spider

The missing sector orb web spider is another spider that can be found in your home, especially around windows.¹¹ Similarly to the daddy legs spider, the missing sector orb web spider is seen throughout the year.¹¹ Their appearance may arouse concern due to having features of the false widow spider, but they do not pose a risk to humans.¹¹ 

Key features of a missing sector orb web spider:¹¹

• Small pale body 
• Dark brown legs with lighter-coloured bans
• The silver-grey pattern on the abdomen 
• Size of up to 1.5 cm (or 0.6 inches)

Zebra jumping spider

The zebra jumping spider is a common spider you may see in the spring to autumn months.¹² Although this spider is most often outdoors, it may also come indoors.¹² The zebra jumping spider is best known for its impressive movement, jumping around 14 times its length.¹³ 

Key features of a zebra jumping spider:^12,13

• Its zebra-like black and white stripes 
• Size  approximately 0.8 cm (or 0.3 inches) 

Lace web spider

The lace web spider is the final spider we will explore in this article. Also known as funnel weavers, these spiders are seen throughout the year but are normally found inside homes during the autumn months.¹⁴ Similarly to the missing sector orb web spider, the harmless lace web spider can be mistaken for the false widow spider.¹⁴

 Key features of a lace web spider:¹⁴

• Brown body
• Yellow patterns on the abdomen
• Size between 0.5 and 1.5 cm (0.2 to 0.6 inches)

Treatment

First aid wound care

When you notice a bite that may be from a spider, you should take the following steps:³

• Clean the wound with soap and water
• Soothe the wound using a wrapped-up ice pack or a cold-soaked cloth
• Keep the bite area raised if you can
• Take painkillers if the bite is painful
• Take antihistamines if the bite is itchy
• Try not to scratch the wound to reduce the risk of infection

Medical attention

You should seek urgent medical care if:

•  symptoms get worse or stay the same over time
• You have had a severe allergic reaction to a bite before
• You develop a fever or chills
• You develop pain in other parts of the body
• You feel dizzy
• You feel nauseous or have vomited

Seek emergency medical care if:³

•  struggling to breathe, or your throat becomes tight
• You are breathing faster.
• Your lips, mouth, or tongue become tight or blue (for darker skin, this may be more visible on the palms of the hands or feet)
• You become very disoriented or confused
• The person who has been bitten has fainted

Healthcare professionals are well-equipped to deal with these types of situations. They will be able to assess the severity of your symptoms, provide the appropriate treatment and monitor your symptoms closely.

If you are ever unsure of what to do when you or someone else is bitten by a spider or insect, always seek medical attention. Whilst waiting for assistance, follow the wound care steps listed above.  

How to prevent spider bites

However, bites from spiders cannot be completely avoided. Here are a few tips to help you avoid spider bites as much as possible:¹

• Vacuum your home on a regular basis.
• When you have to disturb areas that may be hosting spiders, wear clothes that cover more of your body (e.g. long sleeves or boots) 
• Store any wood away from your home 
• Try not to store things under furniture

Conclusion

Spider bites are usually nothing to worry about, and most spiders will not even bite you in the first place. But if you do notice what appears to be a spider bite, take the appropriate wound care approach and monitor your symptoms. Although most spider bites will be harmless, there will be a small number of people who may be allergic to the spider’s venom.

Looking out for signs of an allergic reaction or the bite of a more harmful spider is crucial to ensure that you receive the care that you need. If you notice a spider that may be dangerous, such as the black widow or brown recluse, take extra caution to avoid coming into contact with them. Most importantly, if you are not sure if you or someone else has been bitten by a dangerous spider or having an allergic reaction, always seek medical attention.