By Mary-Jane Pilgrim, Master Gardener

Have you ever gotten a weird red rash or burn after spending time outside? If you were pulling weeds or brushing up against certain plants, you might’ve had something called phytophotodermatitis. It sounds scary, but it’s really just a fancy name for a skin reaction that happens when plant juice meets sunshine.

Here’s how it works: some plants (like wild parsnip, giant hogweed, gas plant (Dictamnus), citrus fruits, dill, parsley, celery, fennel and even carrots) have natural chemicals in them called furanocoumarins. When these chemicals get on your skin and are then exposed to sunlight — especially strong summer sun — your skin can react. It might not hurt at first, but after a day or so you might notice red patches, streaks, or even blistering. It often looks like a burn or a splash mark.

People sometimes mistake it for poison ivy, but phytophotodermatitis is different. Poison ivy causes allergic contact dermatitis due to the urushiol oil in its sap. Phytophotodermatitis is not an allergic reaction, and it doesn’t usually itch. It’s more like a sunburn that was triggered by a plant.

Sometimes the blistering can be quite severe.

The good news? It usually goes away on its own in a few weeks, though it can leave behind darker patches of skin for a while. Severe burns may require medical treatment, including potential debridement (removal of damaged tissue) and skin grafts. Protect the affected area from sunlight for an extended period to prevent further irritation.

To avoid it, wear gloves when gardening, wash your skin after handling plants outdoors, and try to avoid sun exposure right after. And if you’re chopping limes for drinks on a sunny patio — wash your hands and arms!

It’s a sneaky kind of sunburn (or worse!), but a little knowledge goes a long way in preventing it.