Earl Grey tea intoxication

Abstract

Since this type of tea had given him occasional gastric pain, he changed to Earl Grey (Twinings & Company, London, UK), which he thought would be less harmful to his stomach. 1 week after the change, he noticed repeated muscle cramps for some seconds in his right foot.Bergamot oil is a well-known UVA-induced photosensitiser with a strong phototoxic effect, and is used therapeutically in psoriasis, vitiligo, mycosis fungoides, and cutaneous lymphoma.Because of this side-effect, bergamot oil has been widely banned as an ingredient in cosmetics and tanning products.1 Bergamot oil also has a hepatotoxic effect and may cause contact-allergy.The adverse effects of bergamot oil in this patient are explained by the effect of bergapten as a largely selective axolemmal potassium channel blocker,2 reducing potassium permeability at the nodes of Ranvier in a time-dependent manner.3 This may lead to hyperexcitability of the axonal membrane and phasic alterations of potassium currents, causing fasciculations and muscle cramps.3,4 Impaired potassium-channel function plays a pathogenic role in other disorders with fasciculations, myokymia, and cramps such as Isaacs' syndrome, episodic ataxia/myokymia syndrome, and amyotrophic lateral sclerosis.4,5 Hyperexcitability may be enhanced by prolonged opening of voltage-gated sodium-channels due to bergapten.A soothing cup of tea 3,4 Tea is regarded a delicious, aromatic stimulant worldwide.