What is the main characteristic of delayed tanning (DPD)?

The main characteristic of delayed tanning (DPD) is its requirement for melanin to be produced. This process involves a biochemical reaction in the skin that occurs after exposure to ultraviolet (UV) radiation. During DPD, the skin produces melanin, the pigment responsible for the color of skin, hair, and eyes, in response to the damage caused by UV rays. This melanin serves as a natural defense mechanism, absorbing UV radiation and protecting the deeper layers of skin from potential harm.

This characteristic distinguishes DPD from immediate responses, such as immediate pigment darkening, which occurs right after UV exposure without the necessity of melanin production. Delayed tanning typically appears hours or even days after exposure as a gradual darkening of the skin, indicating that the skin is responding to the UV exposure over a longer period. This gradual production and accumulation of melanin is critical to understanding the nature of delayed tanning and how it differs from other immediate reactions of the skin to UV exposure.