Can poison ivy spread by scratching?

A poison ivy rash can seem to spread because new patches keep turning up after the first ones.¹ Skin that got the most oil usually breaks out first, and skin that got less reacts later, so a new patch is often a slower reaction to the same contact.² The rash itself isn't contagious, so touching it won't give it to anyone else.¹ What can spread, to new spots and to other people, is the oil.¹

Right after contact, before you've washed, oil on your hands or trapped under your nails can be carried to new spots, even places the plant never touched.³ But your skin absorbs the oil quickly, so this only happens for a short time.² On clothes, tools and a pet's fur, the oil can last far longer until it's washed off, sometimes for years.¹ So wash your skin with soap and water as soon as you can, be gentle, since scrubbing can rub the oil in, and clean under your nails.³ Then, while wearing gloves, wash whatever touched the plants, including giving your pet a bath it they were exposed.¹³

Scratching is still worth avoiding, but for a different reason; bacteria from under your nails can get into the blisters and cause an infection.¹ To calm the itch, use over the counter calamine lotion or hydrocortisone cream.¹ You can also use cold, wet washcloths as a compress on the itchy skin.¹ The rash usually clears in two to three weeks without additional treatment.²

See a doctor if the rash is around your eyes, mouth or genitals, or covers more than a quarter of your skin.¹ The same goes for pus, soft yellow scabs or a fever.¹ Have a doctor check a child's first rash like this too, since other conditions can cause a similar rash.⁴ Get emergency care right away for trouble breathing or swallowing, or a swollen face, especially an eye swollen shut.⁵