What factors influence dermal blood flow?

Dermal blood flow is influenced by several factors, including the following:

1. Body temperature: Dermal blood flow increases with increasing body temperature, as the body needs to dissipate heat. This is why skin becomes flushed when you are warm or in a hot environment.

2. Local temperature: Local changes in temperature can also cause changes in dermal blood flow. When skin is exposed to cold, blood flow decreases to conserve body heat. In contrast, when skin is exposed to heat, blood flow increases to dissipate heat.

3. Systemic factors: Systemic factors such as blood pressure and arterial tone can also influence dermal blood flow. Low blood pressure or decreased arterial tone can reduce dermal blood flow, while high blood pressure or increased arterial tone can increase dermal blood flow.

4. Hormones: Hormones such as estrogen and progesterone can also affect dermal blood flow. For example, estrogen can cause an increase in dermal blood flow, which is why women often experience flushing or redness of the face during pregnancy or when taking oral contraceptives.

5. Nerves: Nerves play an important role in regulating dermal blood flow. Stimulation of sympathetic nerves can cause a decrease in dermal blood flow, while stimulation of parasympathetic nerves can cause an increase in dermal blood flow.

6. Inflammation: Inflammation can also lead to an increase in dermal blood flow. This is because inflammation causes the release of inflammatory mediators, such as histamine, which causes blood vessels to dilate and increase blood flow to the area.

7. Skin conditions: Certain skin conditions can also affect dermal blood flow. For example, psoriasis and eczema can both cause increased dermal blood flow, while scleroderma can lead to decreased dermal blood flow.