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How are itching and pain detected by nerve endings in the skin?

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skin rash caused by Lyme disease — skin disease Visible alterations in the texture of the skin, such as rashes and hives, can be indicative of serious disease. For example, one of the first signs of Lyme disease is a circular rash in a bull's-eye pattern on the skin.

Itching and pain are detected by specialized nerve endings in the skin, though they function through distinct physiological processes.

Pain Detection

Pain is sensed by pain receptors (nociceptors), which are nerve fibers capable of being excited by mechanical, thermal, or chemical stimuli. These receptors respond to substances released during tissue damage or inflammation, such as bradykinin, serotonin, and histamine.12

The transmission of pain involves two primary types of afferent nerve fibers:
* A delta fibers: Myelinated fibers that conduct impulses rapidly, associated with sharp, well-localized pain.1
* C fibers: Smaller, unmyelinated fibers that conduct more slowly, associated with lingering, poorly localized sensations.1

Itching Detection

Itching is primarily a stimulation of free nerve endings located at the junction of the dermis and epidermis. While itching and pain share common nerve pathways, they are considered distinct sensory types. The release of histamine from cells in the epidermis is a primary trigger for the sensation of itching. Unlike pain, which is often associated with acute tissue damage, itching typically evokes a desire to scratch, which may temporarily interrupt the rhythm of nerve impulses.3