The genus Euphorbia, commonly known as spurge, comprises over 2,000 species of flowering plants. A white, milky substance called latex or sap is exuded when the plant is cut or damaged. This sap functions as a natural defense mechanism against herbivores and pests. This milky fluid is the source of the genus’s potent biological activity, making accidental contact common when handling the plants.
Chemical Composition and Mechanism of Action
The irritating and toxic properties of Euphorbia sap are primarily attributed to a class of compounds known as diterpene esters, specifically phorbol esters. These lipophilic molecules share a similar biological activity that causes cellular irritation. The mechanism of action involves the phorbol esters mimicking a natural signaling molecule in the body called diacylglycerol (DAG).
By imitating DAG, the phorbol esters directly activate an enzyme family known as Protein Kinase C (PKC). This activation is unregulated and continuous, leading to a cascade of cellular responses, most notably inflammation and cell membrane disruption. The constant stimulation of PKC pathways results in the severe irritant contact dermatitis experienced upon skin exposure. The immediate, burning sensation is a direct result of this intense, chemically mediated inflammatory response at the site of contact.
Immediate Health Effects of Exposure
Contact with Euphorbia sap typically results in a reaction known as irritant contact dermatitis. Symptoms begin with a burning sensation, followed by pronounced redness, swelling, and localized pain.
Within hours, the affected skin area may develop vesicles, blisters, or even hemorrhagic bullae, resembling a chemical burn. The symptoms can sometimes worsen significantly over the first 12 to 24 hours after initial contact. Furthermore, some individuals experience a heightened sensitivity to sunlight in the exposed area, known as photosensitivity, which can prolong the recovery period.
Ocular exposure is considered a medical emergency due to the high risk of severe damage to the eye’s delicate structures. When sap enters the eye, it causes immediate and excruciating pain, intense redness, and excessive tearing. The chemical nature of the sap can elevate the ocular pH, leading to a chemical injury of the cornea and conjunctiva.
Clinical effects of eye exposure include conjunctivitis, keratitis (inflammation of the cornea), blurred vision, and temporary blindness. In the most severe and untreated cases, the damage can progress to corneal ulceration, inflammation inside the eye (uveitis), and even permanent vision loss. Even with immediate treatment, the pain and visual symptoms may sometimes worsen over the first day or two before improvement begins.
Ingestion of the sap causes severe irritation and a strong burning sensation in the mouth, lips, tongue, and throat. The irritancy of the diterpene esters causes excessive drooling and difficulty swallowing. Swallowing the sap leads to gastrointestinal distress, including nausea, vomiting, and diarrhea. Severe cases can result in significant irritation and swelling of the oral and gastrointestinal lining.
Essential First Aid and Medical Care
Immediate and thorough decontamination is essential after any exposure to Euphorbia sap to minimize tissue damage. For skin contact, quickly remove all contaminated clothing and wash the affected area immediately with copious amounts of soap and water. Rinsing with water alone is insufficient because the lipophilic phorbol esters are not easily dissolved and can spread on the skin.
The affected skin should be gently washed for a minimum of 15 to 30 minutes, ensuring the sap residue is completely removed. Care must be taken during washing to avoid spreading the sap to other sensitive areas of the body, particularly the eyes. Antihistamines or over-the-counter analgesics may be used to help manage local pain and itching after decontamination.
Ocular exposure requires immediate, continuous, and copious irrigation with clean water or saline for at least 15 to 30 minutes. This long duration of flushing is necessary to attempt to neutralize the chemical injury and remove all traces of the sap. After initial irrigation, a medical professional must be consulted immediately, as eye exposure is considered a medical emergency.
For any instance of ingestion, rinse the mouth with water and spit it out. If the individual is conscious and able to swallow, sucking on ice chips or small sips of clear fluids can help soothe the burning sensation and maintain hydration. If ingestion is suspected, or if symptoms like severe swelling, difficulty breathing, or persistent vomiting occur, contact a regional poison control center or seek emergency medical care.