Mild head injury and concussion

This information is for anyone who has had a mild head injury (also known as concussion or minor head injury) and their family and friends. The information will help both people in the early stages of recovery and those who experience ongoing problems.

In this section:

What is concussion?

Concussion is also often referred to as mild head injury, minor head injury or mild traumatic brain injury (mTBI). Regardless of the terminology used, the occurrence of a head injury in these cases causes the brain to shake back and forth inside the skull, causing mild damage.

Concussion is commonly caused by falls, road crashes, assaults and sports accidents. While most mild head injuries result in no long-term damage to the brain, it can cause temporary disruption to brain function that can last for at least a number of weeks.

Mild head injury/concussion is defined by:

  • Loss of consciousness of less than 30 minutes (or no loss of consciousness)
  • Post-traumatic amnesia (PTA) of less than 24 hours after injury (this is a period where people are confused, act strangely and are unable to remember what has just happened)

It is important to note that only around 10% of reported mild head injuries/concussions involve a loss of consciousness – so it’s important to not solely rely on this as an indicator.

What are the symptoms of concussion?

Mild head injury can leave people with a range of concussion symptoms including dizziness, nausea, confusion or an inability to process or retain information, sensitivity to light, and vision distortion.

In the early stages after a mild head injury, there is a small risk of developing complications that may require emergency treatment. Find out more about the warning signs below. 

While for most people concussion symptoms will resolve themselves in a few days or weeks, some people may find that they persist for much longer. Post-concussion syndrome is the name given to the range of symptoms that continue to occur following a mild head injury or concussion.

When should I seek medical advice after concussion?

After a concussion/mild head injury, it is important that, if possible, you are accompanied by a responsible adult.

While unlikely, there is a small risk of developing complications, so if you experience any of the following concussion signs and symptoms in the next few days you should go to your nearest Emergency Department as soon as possible:

  • Loss of consciousness 
  • Increasing disorientation
  • New deafness in one or both ears 
  • Problems understanding or speaking
  • Loss of balance or problems walking 
  • Blurred or double vision
  • Any weakness in one or both arms or legs 
  • Inability to be woken
  • Any vomiting 
  • Bleeding from one or both ears
  • Clear fluid coming out of your ears or nose 
  • Any fits (collapsing or passing out suddenly)
  • Drowsiness when you would normally be wide awake 
  • Severe headache not relieved by painkillers such as paracetamol

Dos and don'ts in the first few days after concussion

Dos Don'ts
DO make sure you stay within reach of a telephone and medical help in the next few days DON'T stay at home alone for 48 hours after leaving hospital
DO have plenty of rest and avoid stressful situations DON'T drink alcohol until you feel better
DO show this information to a friend or family member who can keep an eye on your condition DON'T take aspirin or sleeping tablets without consulting a doctor
DO take painkillers such as paracetamol for headaches DON'T return to work until you feel ready
DO find out more in our factsheet Mild head injury discharge advice (PDF) DON'T play any contact sport for at least three weeks without consulting your doctor
DO get further information on when to seek medical attention on the NHS website DON'T return to driving until you feel you have recovered. If in doubt, consult your doctor.

The information on this website should not replace a clinical examination. If you have not been examined then contact your GP or call 111. In case of a medical emergency, please call 999. 

Post-concussion syndrome (PCS)

The effects of a concussion can be anything but mild to the person concerned. The symptoms can include nausea, headaches, dizziness, impaired concentration, memory problems, extreme tiredness, intolerance to light and noise, and can lead to anxiety and depression. When problems like this persist, they are often called post-concussion syndrome.

What are the symptoms of post-concussion syndrome?

The symptoms of post-concussion syndrome may include:

  • Headaches
  • Irritability
  • Feelings of dizziness
  • Restlessness
  • Nausea
  • Impulsivity and self-control problems
  • Sensitivity to light
  • Difficulty concentrating
  • Sensitivity to noise
  • Feeling depressed, tearful, anxious
  • Sleep disturbance
  • Fatigue
  • Memory problems
  • Difficulties thinking and problem-solving

How long does post-concussion syndrome last?

In many cases these symptoms resolve themselves within a few days or weeks. However, in some cases problems can persist for months, but still resolve themselves eventually. This can be a frustrating time, as the effects may be subtle and you may not have been told about them.

This may also be the most prolonged period of feeling ill that you have experienced and you may wonder if you will ever feel better. Following the suggestions in our booklet Mild head injury and concussion (PDF) should help to make you feel better as quickly as possible, but be patient with yourself and try not to rush things.

It is important to realise that these symptoms often happen even when there is no damage to the brain and that the fear of having brain injury, even if there is none, can be very distressing and can delay recovery. So it is sensible, if you have these symptoms for more than about two weeks after the injury, or if they are severe and not getting any better, that you see your GP.

It may be appropriate to be referred to a head injury specialist, such as a neurologist or neuropsychologist, for assessment. 

Managing concussion

While there is no single treatment for concussion, with appropriate medical care, plenty of rest and specialist support where appropriate most people will make a good recovery.

It is important that relatives and employers are warned about the possible effects of a mild head injury/concussion, and for plans to be made accordingly. These might include not rushing to return to work, keeping stress to a minimum in the short term, and abstaining from alcohol.

One study showed that almost one third of people with a mild head injury were not working full-time three months after receiving the injury, although other studies have been much more optimistic. Difficulties are certainly made much worse if the person has a mentally demanding job where there is a low margin for error.

Our booklet Mild head injury and concussion (PDF) provides tips and strategies for coping with the effects of post-concussion syndrome. 

Concussion in sport

As with in life in general, accidents and collisions can occur in contact sports – with head injuries commonplace in sports such as football, rugby, hockey and many others. And while rules are in place in such sports to protect players from head injuries, collisions are inevitable in contact sports.

Visit our Concussion in sport campaign page for more information on concussion in sport, including expert opinions, useful downloads, and information on what to do should you suspect concussion.

Recovery from concussion and further information

The general conclusion seems to be that the vast majority of people who experience a mild head injury make a full recovery, usually after 3-4 months. However there is a very small sub-group whose recovery is not so good.

See our booklet Mild head injury and concussion (PDF) for more details, and our factsheet Mild head injury discharge advice (PDF) for important information after sustaining a head injury.

If you would like to discuss any issues relating to mild head injury and concussion, please contact our helpline on 0808 800 2244 or