How Itches Work

The Itch-Scratch Cycle
Studies show that watching someone scratch makes you want to do the same.
Studies show that watching someone scratch makes you want to do the same.
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All this talk of itching has probably made you already start scratching. We all do it. In fact, studies have shown that watching an image of someone scratching can make you want to do the same even more than watching an image of an itch-producing stimuli (like an ant crawling up an arm) [source: BBC News].

Almost all two- and four-legged animals scratch. Scientist even think that fish and fruit flies show behaviors that are probably associated with scratching when they rub up against objects (fish) or carry out robust grooming behaviors (fruit flies). But does scratching help anything?

Scratching interferes with sensations arising from pruriceptors by stimulating pain and touch receptors in same area. No one is really sure of the biochemical pathways that make scratching help the itch, but scientists have found that it has a compulsive effect on the brain. Scratching — even on places that don't itch — can activate areas of the brain associated with memory and pleasure, while at the same time suppressing those areas that are associated with pain [source: Cox].

In fact, scratching brings all sorts of relief. Long distance scratching, where you scratch far from the actual site of the itch, can even help you feel better about that itch. But if you are scratching far from the itch site, think about where you scratch. Studies show that the pleasure you get from scratching different parts of the body varies [source: Live Science].

Probably due to the way sensory nerves are distributed through the body, you get the most intense pleasure from scratching your back and ankles. And part of the key to having a scratch feel great is doing it yourself. Studies have shown that it is more rewarding to scratch your own itch than to have someone scratch it for you [source: Grady].

We can probably all agree that scratching an itch feels great. But, sadly, it's only temporary relief. Scratching can actually be more harmful than helpful if the skin becomes further irritated. So what else can you do to stop an itch?