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Dermatology may seem a bit odd on the surface, pun intended, to be included here. However, anectdotally, sanguinarians frequently mention skin sensitivity to the sun. Sunburning more quickly, and more severely, then non-sanguin friends. So what causes a sun burn? What is the natural response and what is the skin ment to do?

WHAT SKIN DOES

Skin is the first line of body defense. It is layered, oily, and secretes sweat. It protects agains disease and helps with body temperature regulation. In a healthy person, the skin is made of several layers of cells, dead cells on top, and normal cells deeper. the outermost layer, the epidermis, is made of five layers of cells or "stratums". The deepest stratum, stratum basale, divides and creates the cells that move up to the other stratum, getting gradually flatter and becoming the dead cells of the stratum corneum. Three types of specialized cells are also in the epidermis: Melanocytes, Langerhans and Merkel cells. Langerhans cells are part of the immune response, Melanocytes are the pigment forming cells, and we are not yet sure what Merkel cells do. In the dermis, there are two layers, both made of collegen that gives the skin the stretch and move properties it requires to be on the outside of a mobile body. The dermal layer also contains teh follicles for hair, apocrine glands (scent), eccrine glands (sweat), and sebacous glands (oil). the bloodvessels and nerves that provide nutrition to the skin and sensations of touch and pressure are also in the dermal layer.

TANNING AND SUNBURNS

To look into what causes a sunburn and sun tan, we look mostly at the epidermal layer, specifically the melanocytes. As stated above, the melanocytes are responsible for making melanin in the presence of UV radiation. This is a protective pigment that helps to absorb UV radiation and prevent it from causing solar and free radical damage to DNA. This is where skin cancer comes in, UV raditation production of free radicals leading to damage to DNA and improper replication, which in turns leads to improper replication of cells.

Two types of melanocyte changes are known: immediate and delayed. In immediate changes, the skin darkens immediately upon exposure to primarily UV-A radiation. It is an oxidation of melanin that was already in the cells. When UV exposure is discontinued, the skin pigmentation begins to fade immediately. The delayed pigmentation changes occur after exposure to UV-B light. They can take 2-3 days to peak even after exposure is discontinued. It is created by an up-regulation of tyrosinase, increased numbers of melanocytes, increased numbers of melanosomes and increased transfer of melanosomes to skin cells (keratinocytes).

In a sunburn, the body's ability to produce melanin for protection is overwhelmed and the epidermis becomes damaged. The UV radiation causes death of the cells ofthe epidermis and dermal irritation. This leads to the redness, pain, and sometimes blistering of a severe sunburn. The skin peeling observed a few days after the sunburn is the body shedding these dead and damaged cells after producing new ones. If the burn is just readness, then the delayed pigmentation discussed above will develope into a tan. If the burn is severe, however, causing peeling and blistering, the cells that normally would create the melanin are lost and do not respond, thus no tan is formed.

Whether one tans or burns, and to what degree of tan, depends not only on the UV exposure itself, but also on genetic factors. Very light skinned people of northern European descent do not tan as deeply as those of darker skin tones such as Hispanic or Middle Eastern descent. This fact needs to be taken into account when looking at anectdotal evidence of sanguinarians, as 67% of self-identified sanguinarians in a survey reported to be of at least partial northern European ethnicity (59% of total Eastern European ethnicity).

TESTING THE ANECTDOTAL EVIDENCE

Before we can go further into wether skin should be seriously looked at as part of the sanguinarian syndrome, we need to prove it rather then rely on anectdotal evidence. To do so, one would need to test the time to tan/burn of several sanguins. Average human time before burning (without sunscreen) is 20-40 minutes to times would ahve to be statistically different from that. If it is statistically different, skin biopsies to look at the number and nature of melanocytes would be an interesting follow-up.