I probably shouldn’t have delved into this topic. It’s horribly complicated. I was curious about the fact that I have an itchy spot under my left collar bone (hard to reach!). My little itch is small potatoes compared to the suffering that many people endure.
Dermatology websites list the causes of itching: extremely
dry skin; bug bites; skin conditions, such as eczema, hives, and psoriasis; skin
cancer; warning signs of diseases, especially of the kidney and liver, and
overactive thyroid gland; allergic skin reaction; reaction to a plant or marine
life; medication or cancer treatment; nerve problem. Scratching alleviates itch
by interrupting it: the pain of scratching creates the pleasure of relief.
One in five people experience chronic itch in their lifetime,
often caused by cancer, a skin condition, or liver or kidney disease. (There
are no medications for it.) Some unlucky people have a rare disease in which
itching can be unrelenting and extreme.
The kind of itching that’s acute (not chronic), and caused by
irritants such as poison ivy, is caused by the immune system’s reactions: immune
cells secrete histamine that activates the nervous system, making you itch and
scratch. Medications, such as steroids or antihistamines, may help in these
cases. Some people itch for no clear reason and their bodies don’t respond to
steroids or antihistamines.
In 2007, neuroscientists figured out itch-specific nerve receptors
that are triggered by substances other than histamines. Some itching—such as
that caused eczema—is caused by the body’s secretion of certain proteins (cytokines)
that rev up the immune system. In 2017, the FDA approved a drug called
Dupixent, which reduces the immune system's overreaction that causes
eczema. Apparently, it works. It can be yours for $59,000 a year (retail).
My research yielded nothing in the way of explanation for my
little itch--at least nothing definitive. I can live with it.
For an introduction to this blog, see I Just Say No; for a list of blog topics, click the Topics tab.
Another cause for itching is diabetes, and lots of older people have that issue. A hot shower really fees good, but it is not good for dry itchy skin.Using anti itch lotion does help dry skin.
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