As the pain caused by trigeminal neuralgia is often felt in the jaw, teeth or gums, many people with the condition visit a dentist before going to a GP.

The dentist will ask you about your symptoms and give you a dental X-ray to help them investigate your facial pain. They'll look for common causes of facial pain, such as a dental infection or cracked tooth.

Trigeminal neuralgia is often diagnosed by a dentist, but if you have seen a dentist and they could not find an obvious cause of your pain, you should visit a GP.

There's no specific test for trigeminal neuralgia, so a diagnosis is usually based on your symptoms and description of the pain.

If you've experienced attacks of facial pain, the GP will ask you questions about your symptoms, such as:

• how often do the pain attacks happen
• how long do the pain attacks last
• which areas of your face are affected

The GP will consider other possible causes of your pain and may also examine your head and jaw to identify which parts are painful.

If your GP does think you could have trigeminal neuralgia then they may refer you to a specialist for further testing.

Ruling out other conditions

An important part of the process of diagnosing trigeminal neuralgia involves ruling out other conditions that cause facial pain.

By asking about your symptoms and carrying out an examination, the GP may be able to rule out other conditions, such as:

• jaw or dental problems
• cluster headaches
• post-herpetic neuralgia – a type of nerve pain linked to shingles

The GP will also ask about your medical, personal and family history when trying to find the cause of your pain.

For example, you're less likely to have trigeminal neuralgia if you're under 40 years old. Multiple sclerosis (MS) may be a more likely cause if you have a family history of the condition or you have some other form of this condition.

However, trigeminal neuralgia is very unlikely to be the first symptom of MS.

A MRI scan is often used to help with the diagnosis of trigeminal neuralgia.

An MRI scan uses strong magnetic fields and radio waves to create detailed images of the inside of your body.

It can help identify potential causes of your facial pain, such as inflammation of the lining of the sinuses (sinusitis), tumours on one of the facial nerves, or nerve damage caused by MS.

An MRI scan may also be able to detect whether a blood vessel in your head is compressing one of the trigeminal nerves, which is thought to be the most common cause of trigeminal neuralgia.