While the presence of giant hogweed has been confirmed in multiple Virginia locations, experts at Virginia Tech say there is no evidence the dangerous weed with toxic sap is spreading widely.

Still, those who come across the plant should take precautions.

Stephanie Lareau, an assistant professor of emergency medicine at the Virginia Tech Carilion School of Medicine, offers these tips for dealing with exposure to the poisonous plant:

If someone thinks they’ve come in contact with giant hogweed, what should they do?

Immediately wash the area with large quantities of cold water to attempt remove the sap from the skin. A mild soap can also be used. Avoid exposure to the sun; if you must be in the sun, make sure to use sunscreen.

How would someone know that it’s time to head to the emergency room?

Any evidence of skin changes like redness or blistering should prompt medical attention.

How would medical experts treat the exposure, both in the short-term and the long-term?

The treatment depends on the severity of the exposure. Minor skin irritation may be treated with topical steroid cream and oral nonsteroidal anti-inflammatory drugs (NSAIDs), whereas more extensive burns may require surgical care in a burn center.

What is it about hogweed that makes it so toxic to humans?

Hogweed contains phytotoxins which are chemical compounds like psoralen or furocoumarins which are activated by ultraviolet (UV) light. They then cause damage to human DNA, causing significant burns.

Are there other medical effects of giant hogweed, other than skin burns?

Giant hogweed can cause ocular (eye) burns which can lead to blindness. Burns can lead to changes in skin pigmentation and permanent scarring.

From a medical standpoint, just how dangerous is giant hogweed?

The danger of giant hogweed is dependent on the amount of exposure and subsequent exposure to sun. Early recognition and treatment is very important in preventing potentially life threatening reactions.

What else is important about the medical impact and treatment of hogweed?

Hogweed is a relatively new occurrence in Virginia, so many clinicians may not be very familiar with it. Any history patients can provide about exposure can help guide medical care.