The Manchineel (Hippomane mancinella) is a member of the Eurphobias or spurge family and produces one of the most potent tree toxins known.1,2 Exposure to the toxic sap (which contains Diterpene esters of the tigliane phorbol and daphnane types) can cause severe dermatitis and ophthalmitis consisting of erythema, blistering, swelling, inflammation, pustulation, and conjunctivitis with painful burning sensation typical of Chemical Irritant Contact Dermatitis (CICD).3–5 Exposure most commonly takes place when individuals take refuge from the rain under a Manchineel tree. Ingestion of the Manchineel fruit (Beach Apple or “Manzanilla de la muerte”) can cause severe swelling, ulceration, and hemorrhage of the oral and gastrointestinal mucosa which has been reported to be fatal in extreme cases.5,6 Systemic manifestations can be significant and persistent bradycardia requiring permanent pacemaker insertion has been ascribed to Manchineel toxicity.7 The toxin has been used in bellicosities by aboriginals from Florida to the southern Caribbean by treating arrow tips or poisoning water.8,9 Ponce De Leone is said to have died subsequent to a poisoned arrow wound containing Manchineel toxin in West Florida following an encounter with the hostile Calusa indians.9 The Manchineel is found in Florida, the West Indies, and Central and South America.1,2 Most trees have signs warning of their dangers, but these are often poorly visible or missing. The tree is on the endangered species list in Florida due to eradication efforts; however, it continues to be valued in coastal regions for the excellent shade it provides and root system which helps prevent beach erosion.1,2 We report four cases of Manchineel dermatitis and ophthalmitis that occurred when four students (100% attack rate) took shelter under a Manchineel tree during a rain storm.
We report an outbreak of Manchineel dermatitis and ophthalmitis in four students from North America who visited the island of Bequia, West Indies. The exposure resulted from taking shelter during a rain storm under a Manchineel tree. Manchineel exposure and ingestion can lead to severe and even fatal disease.
A 22-year-old Caucasian male had direct exposure with the bark and leaves of the Manchineel tree as well as leaf runoff from the rain while taking refuge. He was wearing bathing trunks, sun glasses, and a brimmed cap. His exposure lasted 1 hour and his onset of symptoms was approximately 12 hours. The symptoms included “burning” of the skin, erythema, swelling of the affected areas, and some blistering at areas of direct contact (face, abdomen, arms, and legs). There was no conjunctival irritation noted. He applied “Benadryl” cream shortly after the “rash” appeared and had resolution of all symptoms and lesions in 5 days with no scarring.
A 23-year-old Caucasian female had direct contact with the bark and leaves of the Manchineel while repairing from the rain, leaning against the tree trunk, and touching the leaves. She was wearing a bikini and strapless dress during her exposure of 1 hour. She did not have a brimmed cap during that time. Twelve hours after her exposure she noted the onset of severe pain, erythema, and swelling of her eyelids and face. This extended rapidly to all of her exposed skin including chest, arms, and legs with accompanying burning and irritation. The lesions progressed with conjunctivitis and blisters including the eyelids (Figure 1) and several of her body surfaces. Healing occurred in about 5 days with mild scarring of the left upper eyelid. She was treated with oral corticosteroid and bathing of the skin to remove remaining toxin.
A 23-year-old Caucasian male stood under the Manchineel tree for approximately 40 minutes. He made no direct contact with the tree or its leaves. His onset of symptoms was about 30 minutes after the exposure. His initial symptoms included facial burning, erythema, and itching followed by swelling of his lips and ears. The lesions progressed to his anterior neck and chest. He noticed itching of his eyes, but no erythema. The symptoms subsided after approximately 2 hours. He applied vinegar at the recommendation of a local restaurateur with rapid resolution of his “rash” and symptoms.
A 25-year-old Caucasian male took refuge under the same tree as subjects 1, 2, and 3 during a heavy rain storm. He was wearing bathing trunks and brimmed cap. The duration of exposure was approximately 40 minutes and he denied direct contact with the tree. Onset of mild burning of his face, nose, and forehead accompanied by mild erythema occurred about 30 minutes after the exposure. He did not develop itching or erythema of his conjunctiva. No treatment was administered and the symptoms resolved spontaneously in about 40 minutes.
This outbreak demonstrates the spectrum of Manchineel toxin dermatitis/ophthalmitis resulting from both direct contact and indirect exposure by merely standing under the tree during a rain storm. In our cases those subjects who had longer and more direct contact with the tree had worse symptoms and manifestations of both dermatitis and ophthalmitis. Of interest is the later onset of the more severe presentations in those who had direct and more prolonged contact. This may be related to the concentration of the toxin (soluble diterpene esters) when delivered by direct contact with the latex versus indirect contact such as rain water runoff from leaves. Ingestion of the Manchineel fruit can cause severe disease of the oral mucosa and gastrointestinal tract with inflammation, ulceration, hemorrhage, and even death.4,6 None of the subjects we report were aware of the dangers of Manchineel exposure nor did they observe the warning sign that was 40 ft. from where they were located. Fortunately, none of the cases reported herein tried the “forbidden” fruit. Given the growing number of visitors to the West Indies and Central America we believe that information regarding Manchineel avoidance should be considered as part of travel preparation for visitors to the beaches of the Caribbean Basin where the tree is a common part of the indigenous flora. Toxicity is related to direct contact with the tree (leaves, fruit, trunk, branches, or the latex exuded at sites of injury to the tree's structures), to water runoff from the tree during rain storms, to consumption of the fruit (the most risky exposure), and smoke released from burning of any of the tree's parts. This is especially important for long stay “education tourists” in the Caribbean Basin given their increasing numbers and greater likelihood of exposure due to their frequent visits to the beaches of the region especially during the “rainy” season. Treatment of Manchineel dermatitis and ophthalmitis should consist of vigorous cleansing to remove the toxin containing latex and symptomatic measures including cool compresses and anti-irritants.10 Corticosteroids have been suggested as useful in severe cases especially involving the eye.10
Declaration of Interests
The authors state that they have no conflicts of interest.