Congenital nevomelanocytic nevus; “split” of the eyelid. A sharply demarcated, brown plaque, involving the upper and lower eyelids in a 45-year-old Asian female. Nevomelanocytes migrate from the neural crest to the skin after the 10th week in utero but before 24 weeks when splitting of eyelids occurs.
Bee, wasp, yellow jacket, hornet or fire ant stings most often trigger allergic reactions. However, most people are not allergic to insect stings and may mistake a normal sting reaction for an allergic reaction.
The effect of contact with a sea urchin. Sea urchins are a gastronomic delight when prepared properly, but a cutaneous torture when stepped on unprepared. The echinoids have spines that in some species are several inches long. Driven into skin when one steps or falls on or brushes against the creatures, the hard spines break and lodge in skin. Pain is inevitable, and secondary infection is nearly inevitable if they are left in. Nothing but tedious and meticulous extraction of every one of dozens, possibly scores, of spines is required for relief.