WHY DO NETTLES STING ?
The name ‘nettle’ comes from an old Scandinavian word ‘Noedle’ – meaning ‘needle’ in reference to the stinging parts – which underrates this most useful plant. The stinging part of a nettle is its defense from herbivorous animals. The leaves are covered with tiny hairs that terminate in a small head covered by a silicified, cellular membrane. The fragile ends break off even when the leaf is gently touched, or especially when gently touched if you believe the old adage:
Tender handed stroke a nettle,
And it stings you for your pains;
Grasp it like a man of mettle,
And it soft as silk remains.
I certainly don’t. They just sting even more ! As the needle breaks off into the skin it injects its venom and causes local irritation and later an interesting tingling sensation that can last all day or even longer. The Romans used to sting themselves deliberately with nettles to warm up their skin in a cold northern climate.
The venom was once thought to be made of formic acid – similar to an ant sting but recent research shows a more complex mix. Other chemicals include histamine, 5-hydroxytryptamine (serotonin) and acetylcholine. A fourth ‘mystery’ ingredient has yet to be identified.
Dock plants are often to be found near stinging nettles and rubbing dock leaves on the skin until it goes green can relieve the mild venom. Some people put sticky tape over the sting and then pull it off to remove the needles but I am not sure if this works.