Parkinson's disease is a progressive nervous system disorder that affects movement that affects thousands of Irish people.
Its symptoms usually start gradually, often starting with a barely noticeable tremor in just one hand.
Tremors are common, but the disorder also commonly causes stiffness or slowing of movement.
READ MORE: Parkinson's disease symptoms as study identifies two early signs of condition
While there are few treatments and no cure for Parkinson's disease, several signals could indicate whether someone has the condition.
Although lack of movement and stiffness are often indicators of the illness, scientists have said that the skin can also provide signs.
The American Parkinson's Disease Association (APDA) says Seborrheic Dermatitis is "commonly found in people" with Parkinson's disease.
The condition causes "patches of scaly, red skin, and dandruff, primarily on the scalp and on the oily parts of the face such as the sides of the nose".
However, it is important to note this form of dermatitis is particularly prevalent among the general population.
The APDA says in Parkinson's patients, the condition is "thought to be caused by over-secretion of oils from the sebaceous glands in the skin.
"In much the same way that dysfunction of the autonomic nervous system cause non-motor symptoms in Parkinson's such as blood pressure dysregulation and urinary abnormalities, autonomic dysfunction of the nerves that control the oil glands of the face can cause seborrheic dermatitis".
Furthermore, a recent study found this form of dermatitis was associated with an increased risk of Parkinson's.
The HSE describes dermatitis as "a type of eczema caused by contact with something that irritates your skin or something you are allergic to."
Eczema is the name for a group of conditions that cause skin to become dry and irritated.
The HSE says: "Contact dermatitis usually improves if you avoid what is causing the problem. Treatments are also available to help ease the symptoms."
It adds: "If you can avoid the irritants or allergens that cause your symptoms, your skin will clear up."
While dermatitis is a common skin condition, for many, it can be chronic and, as a result, cause deterioration in mental health due to lowered self-esteem.
In recent years, studies have begun to look at whether this forms part of a snowballing effect and whether poor mental health can be linked to worsening dermatitis.
A review of studies related to dermatitis, eczema, and mental health has found eczema increases the risk of anxiety or depression.
Published in the journal PLOS ONE, the research was conducted by the Sixth Affiliated Hospital of Kunming Medical University in China.
Researchers discovered eczema was associated with a 64 per cent increased risk of depression and a 68 per cent increased risk of anxiety.
As to why eczema causes this increased risk of anxiety, Beth Goldstein said: "Social isolation and stigmatisation can certainly occur as many patients experience their dermatitis on areas of their bodies that are public such as the face, neck, and hands."
Goldstein added this could make "intimate relationships very difficult to navigate" given the aesthetic nature of eczema and dermatitis.
Meanwhile, Dermatologist Vivian Shi added: "It is extremely important to address the mental health component of eczema because the stress can cause flare-ups or worsen existing symptoms."
Shi said treating the mental health side of eczema was "crucial to maximise treatment benefits".
As a result, this research provides a new avenue for understanding the relationship between skin conditions and mental health.
Despite this study review, further research is required in order to identify a link between dermatitis and mental health.
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