I recently came across this interesting condition called dermatographic urticaria, also known as dermatographism or “skin writing”. The more common name for urticaria is hives, or bumpy/red skin rash that may be caused by allergies. Dermatographism is a prevalent type of urticaria, especially in young adults. If you have a friend with “sensitive skin” that reddens and swells upon contact, s/he may have actually have dermatographic urticaria.
Most interestingly, this is thought to be caused by the release of histamine from mast cells, which are involved in the allergy pathway. The membrane around the mast cell is weak and breaks under physical pressure, which causes the characteristic raised red skin.
http://www.ncbi.nlm.nih.gov/pubmed/6166647
Since we’ve been studying lipids, I though this was an appropriate reminder of how important the cell membrane is. The composition of the phospholipid bilayer directly affects its fluidity, and in this case, it is too fluid. The cholesterol, protein and lipid concentrations may need to be adjusted, with more long-chain saturated phospholipids.