SCIENCE PHOTO LIBRARY SCIENCE PHOTO LIBRARY
Red line on the back of a six year old boy with dermographia. This skin condition causes raised red itchy weals on areas of the skin that have been rubbed or scratched. This is due to overactive mast cells, a type of immune cell that release histamine. What causes the mast cells to become overactive is not known. Treatment is with antihistamines and avoidance of triggers.
Model release not required. Property release not required.