Dr Bernadette Carr is here to answer your questions

Q. I caught my hand in a door a week ago. It was sore at the time and yesterday I noticed a bruise underneath one of my fingernails. Will it fade on its own?

A. A bruised nail or subungal haematoma is common after an injury to the nail bed and it should fade by itself over a few weeks.

A painful condition. the most common injuries to the nails are crushing injuries such as the one you sustained or hitting it with a hammer, cutting injuries from knives or machinery and tearing the nail by catching it on something.

The nail consists of three different layers:

* The nail bed which is responsible for nail growth.

* The nail itself.

* The cuticle (eponychium) and raised skin either side of the nail.

When the small blood vessels (capillaries) under the skin break following trauma or an injury, the blood from these vessels leaks into the soft tissue under the skin.

A subungal haematoma is a collection of blood between the nail and nail bed. Bruising is more common in some people — in the elderly the skin is thinner and the underlying tissue is more fragile.

Initially bruises are blue or purple and gradually fade through shades of green or yellow.

To keep nails healthy and to avoid injury, consider the following general suggestions:

* Always wear rubber gloves for any work involving water.

* Avoid damaging the cuticles when manicuring your nails.

* Only ever use the gentlest of nail brushes to clean your nails.

* Don’t bite your nails.

* Protect your nails if doing physical work such as gardening by wearing gloves.

The vast majority of bruises will fade within two weeks, if the bruise is still there beyond that or you experience pain then I would suggest that you make an appointment with your GP, who can examine your hand and fingers to check that there is no underlying damage such as broken bone following your injury.

Q. I am a woman in my 40s. Over the last couple of months I have pain in the base of my right thumb, initially it was when I tried to grip or open something but now it is sore when I am not using it. What should I do?

A. There could be a number of reasons for the pain you are experiencing; some would depend on whether there was a previous injury to the thumb. It is possible that the pain might be caused by either trigger finger or arthritis of the thumb, both of which cause pain at the base of the thumb.

Trigger finger causes the finger to lock after it is bent and is common in the thumb, ring and little finger.

It happens when the muscle pulling the tendon attached to the finger bone forces the finger to bend towards the palm.

The reason is unclear but it is possible that overuse or repetitive use of the palm causes inflammation in the palm.

Thumb arthritis happens when the cartilage at the ends of the bones in the thumb joint wears away.

This can cause pain, swelling and a decrease in both strength and range of movement which can make it difficult to do simple tasks.

Thumb arthritis and trigger finger are both common in women over 40. To ease the pain here are some general suggestions for you:

* Try to rest your thumb.

* Applying heat or cold to the thumb may ease the pain.

* Take a painkiller or anti-inflammatory.

* Gently massage the base of the thumb.

It is important to get a diagnosis and I would advise you to make an appointment with your GP, who can examine your thumb to find the underlying reason for the pain and advise on the appropriate treatment.

Depending on the diagnosis, you may need to see a bone specialist.