What are histamines?

Histamines are chemicals produced by the immune system in response to injury or allergens. They play a crucial role in the body's defense mechanisms by initiating inflammatory responses. When the body encounters an irritant, histamines are released to help dilate blood vessels and increase permeability, allowing immune cells to access the affected area more easily. This process is vital in flushing out irritants, mobilizing the immune response, and promoting healing.

The other options do not accurately define histamines. For instance, chemicals released by hair follicles pertain to different substances related to hair growth and skin oil production. Collagen-building compounds are involved in skin structure but are unrelated to histamines. Waste products from skin cells refer to byproducts of cellular metabolism, which do not describe the function of histamines in the immune response. Understanding histamines is essential in esthetics since they can affect skin reactions during treatments and procedures.