Chemistry of tulips and tulip fingers

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‘Tulip fingers’ might sound like a bizarre floral-themed version of Edward Scissorhands, but it’s actually a condition that can be caused by skin contact with tulip bulbs. It’s common amongst workers in the tulip industry, whose jobs involve sorting and packaging of tulip bulbs. This graphic takes a look at the compounds behind the condition.

‘Tulip fingers’ is caused by contact with tulip bulbs or sap, and appears as redness, eczema, or even pustules on the thumb and fingers. It’s a type of allergic contact dermatitis – an allergic reaction that causes the skin to redden and inflame. Compounds caused tuliposides and tulipalins, found in the sap of tulips and their bulbs, are to blame for this reaction.
 
Tulips make tuliposides from a combination of glucose and other organic compounds. Tulipalins form when tuliposides break down. Both compounds can trigger allergic skin reactions, and tulipalin A is a key causative agent. Chemical groups in skin proteins attack parts of these molecules, making substances that lead to an immune response in the body. This is the allergic reaction that ‘tulip fingers’ refers to.
 
So, are tulips the fair but foul flowers in your spring garden, harbouring compounds intended to trigger a nasty rash? Not quite. The tuliposides and tulipalins aren’t intended to deter humans, but other organisms. Tuliposides break down to form tulipalins when soil fungi attack the tulip. The tulipalins have a strong antifungal effect to combat infection. Humans are just unintended collateral damage from the fight between plant and pathogen.
 
Unless you’re handling tulip bulbs or coming into contact with tulip sap a lot, tulip fingers isn’t a condition you have to worry about. If handling tulip bulbs, studies have shown that the allergens can penetrate some protective gloves. Nitrile gloves, however, are effective in stopping them contacting the skin. It’s also noted that some types of tulip are more problematic than others. Preludium, Rose Copeland, Clara Butt and Le Nôtre varieties are types more likely to cause allergic reactions.