The skin is the largest organ, and also one that is in plain sight. In our everyday lives, the focus is on the outer appearance of our skin, but the skin does much more than look pretty. We look at the important functions of the skin and help you identify when your skin might need a little help from you.
Barrier Function
One of the most critical functions of the skin is to act as a protective shield between the external world and the body. At a basic level, we would turn into a mummy under arid conditions without a barrier function. Even small defects in the barrier function appear on the skin as rashes, dryness, or other visible symptoms.
- Blocks harmful antigens like viruses, bacteria, and fungus from entering our bodies.
- Regulates moisture levels.
- Problems with the barrier function often result in visible symptoms such as inflammation, dry, or cracked skin.
- Skin conditions like atopic dermatitis are associated with a weakened barrier function.
- Moisturizers can help to reinforce the barrier function and is a must-have item for those with a compromised barrier function.
Thermoregulation
Humans have a very narrow range of internal body temperature that they can function at. A mere 2 degree Celcius shift away from 37 is all it takes to fall into hypothermia or hyperthermia, both being very dangerous states.1 Precise thermoregulation is a necessary adaptation for humans, given the wide ranges of climates that humans have successfully inhabited.
- Sweat plays an important role in regulating temperature.
- Evaporative cooling efficiently drops the body temperature when it becomes overheated.
- The hair on the skin also helps to control body temperature. Goosebumps cause the hair to stand upright to keep heat in the cold, while the hair lies flat to promote heat loss in warm environments.
- Although powerful, there are limits to the body’s ability to regulate temperature. Wearing appropriate clothing is important.
- Sweating is a powerful and efficient method of cooling but is not without its costs. During vigorous exercise, we can lose several pounds of water through sweating. It’s important to replace the water loss.
Photoprotection
Humans are naturally more vulnerable to sun exposure than many animals. We don’t have thick fur, and we don’t wallow in mud regularly. We do have some defense, however, and our skin provides us with melanin, which is the pigment that produces color.
- UV exposure is a powerful environmental hazard that causes premature aging, skin cancer, and many other skin conditions.
- Melanin produces color (tan) in the skin and is activated in response to sun exposure. The color scatters light, providing it with a degree of protection from future sun exposure.
- The effectiveness of melanin can be seen by the difference in melanoma incidence between Caucasians and African Americans, as well as differences in biological vs chronological aging.2
- Melanin is not a replacement for sunscreen or good sun safety practices, however.
- While photoprotection is a part of the skin’s function, its protective powers are limited. It’s estimated that a tan provides less than 3 SPF.3 Staying in the shade, wearing longer clothes, and applying sunscreen can help your skin on the job.
Immunological Protection
The skin plays an important role in immune function. The skin’s defense against antigens like bacteria, fungi, and viruses isn’t just its physical barrier function, though this plays an important role. Once these antigens infiltrate the skin, immune cells like macrophages digest these invaders.
- Reactions like inflammation are an important part of the immune system.
- Several cells in the skin play important roles in identifying antigens, and also produce antibodies to various threats.
- The immune function of the skin acts as a first-line defense against infection by triggering inflammation.
- The downside is that sometimes the immune function can work against you. Many skin conditions, like atopic dermatitis, have a strong immunological component where inflammation is triggered in response to substances that aren’t normally harmful.
- Make sure that your skin is protected. If you have dry cracked skin, make sure that you moisturize. This helps protect its barrier function but also helps reduce the load that your immune functions need to play as well.
- Lifestyle factors are relevant as well. Diet, exercise, and living well can help boost your immune system.
1https://www.sciencedirect.com/science/article/pii/S1566070216300017
2https://dermletter.com/science/ethnicity-skin-aging-genetics/
3https://www.scientificamerican.com/article/fact-or-fiction-a-base-tan-can-protect-against-sunburn/
