The symptoms of haemophilia depend on how severe the condition is, but the main sign is prolonged bleeding.

The bleeding may happen spontaneously. For example, this could be:

• sudden nosebleeds
• bleeding gums
• bleeding inside your joints and muscles

The bleeding may also happen after a medical or dental procedure, such as having a tooth removed.

The severity of haemophilia is determined by the level of clotting factors in a person's blood:

• mild haemophilia – between 5% and 50% of the normal amount of clotting factors
• moderate haemophilia – between 1% and 5%
• severe haemophilia – less than 1%

Children born with mild haemophilia may not have any symptoms for many years.

Mild haemophilia usually only becomes apparent after a wound or surgery, or a dental procedure such as having a tooth removed. These events could cause an unusually long period of bleeding.

Children with moderate haemophilia are affected in the same way as those with mild haemophilia, but they also bruise easily.

They may also have symptoms of internal bleeding around their joints, particularly if they have a knock or a fall that affects their joints. This is known as a joint bleed.

The symptoms usually begin with a tingling feeling of irritation and mild pain in the affected joint – most commonly the ankles, knees, and elbows. Less commonly, the shoulder, wrist, and hip joints can also be affected.

If a joint bleed is not treated, it can lead to:

• more severe joint pain
• stiffness
• the site of the bleed becoming hot, swollen, and tender

The symptoms of severe haemophilia are similar to those of moderate haemophilia. However, joint bleeding is more frequent and severe.

Children with severe haemophilia have spontaneous bleeding. This means they start bleeding for no apparent reason.

For example, this could be:

• nosebleeds
• bleeding gums
• joint bleeds
• muscle bleeds

Without treatment, people with severe haemophilia can develop:

• joint deformity, which may require joint replacement surgery
• soft tissue bleeding
• serious internal bleeding

There's a small risk of bleeding inside the skull, known as a brain or subarachnoid haemorrhage. It's estimated that 3 in 100 people with moderate or severe haemophilia will have a brain haemorrhage. 

However, spontaneous bleeding inside the skull is uncommon and usually only caused by a head injury.

Bleeding in the skull should be treated as a medical emergency.

The symptoms of a brain haemorrhage include:

• a severe headache
• a stiff neck
• being sick (vomiting)
• a change in mental state, such as confusion
• difficulty speaking, such as slurred speech
• changes in vision, such as double vision
• loss of co-ordination and balance
• paralysis of some or all of the facial muscles

Call 999 for an ambulance if you think someone is having a brain haemorrhage.