The hives appeared the day after my two-week course of antibiotics ended. I lightly scratched an itch on my arm and, moments later, red welts surfaced along the path left by my fingernails.
Those welts faded within half an hour, but more quickly replaced them, taking the shape of whatever object provoked them. Unnerved, I did what any logical person would do: Search the internet. Apparently I had a condition called dermatographia, or “skin writing.”
“It’s probably more common than people think,” says Andrea Kalus, M.D., a dermatologist who practices at UW Medical Center Roosevelt. Doctors classify dermatographia as a type of urticaria, or hives, and suspect it is a histamine reaction.
“It’s like an alarm going off in the skin, alerting the immune system that there might be a breach in the wall. It allows extra blood flow and immune chemicals to come into the area,” Kalus says.
Doctors don’t completely understand dermatographia. It can be short-lived or chronic, severely itchy or mildly so. One recent study showed it can be a kind of “delayed hypersensitivity” reaction to penicillin, typically beginning six hours to several days after exposure. The authors note that amoxicillin can also cause a reaction after treatment ends—exactly what happened to me.
A Chronic Condition—and an Artist's Inspiration
For Ariana Page Russell, who has chronic dermatographia, the exact cause has been harder to pinpoint. Growing up, her skin was sensitive and flushed easily, and once she broke out in a rash after consuming one of her cousin’s bubblegum-flavored penicillin pills. She first noticed welts as a teenager but didn’t think much of them.
Russell was diagnosed in 2004 when she was a University of Washington graduate student in photography. While working on a project involving kelp, she scratched her knee and noticed kelp-shaped patterns on her skin. She photographed them.
“When I had peers and professors in for a visit, they didn’t care about the kelp photographs—they gravitated to the skin stuff,” Russell says. “I didn’t have any answers for them. They were like, ‘There’s something else going on here—this isn’t normal!’” She went to the doctor soon after.