From yellow dandruff to thinning – the signs of 3 diseases lurking in your hair

HAIR is an important part of many people's identity.

So when it starts falling out, or looking less than its best, it can be very distressing.

And in some cases, changes to your hair can be a sign of a serious disease.

1. Parkinson's disease

While white dandruff is perfectly normal, yellow dandruff can be a sign of Parkinson's disease.

Parkinson's is a neurological disease that worsens over time.

Around 145,000 people live with the condition in the UK.

It is usually associated with tremors, stiffness and slow movement.

Yellow dandruff is caused by seborrhoeic dermatitis, a condition where areas of the skin that have lots of sweat glands, (such as the scalp) become red, itchy, sore and flaky.

According to the charity , people with the disease are prone to the skin condition.

Although there is no cure for Parkinson's, there are several different treatments, therapies and support available to help manage it.

2. Alopecia

If you notice small patches of hair loss - around the size of a coin - you could be suffering from a form of alopeica areata.

The autoimmune disease can also appear on the body including the beard, eyebrows, eyelashes or body hair, including pubic hair.

According to the charity , around 400,000 people in the UK either have the condition or have had it in the past. 

It happens when cells attack the hair follicles, stopping them from producing more hair.

The cause is unknown but iron deficiency and stress could trigger the condition, although may experts dispute this.

In some cases, alopeica areata can turn into alopecia totalis, when hair loss can spread across the entire head, or alopecia universalis, when it affects the entire body.

There is currently no cure for the condition, however, there are a several of treatments available, but none are guaranteed to work.

Usually, in patchy alopecia areata, hair will regrow over a few months or years, but regrowth is not guaranteed. 

However once the condition has developed to alopecia totalis or universalis, the chances of full regrowth become smaller. 

3. Cancer

Red or purple blotches on the scalp or hair line can be a sign of a rare but deadly blood vessel cancer.

Angiosarcoma develops in the inner lining of blood vessels and lymph vessels.

It can appear any place in the body, but typically occur in the skin on the scalp, head or neck.