Calabar bean swellings, also known as Calabar swellings, refer to localized, painless, and non-inflammatory swellings that are often observed after being bitten or stung by certain insects or worms. These swellings are named after the Calabar region in Nigeria, where they were first identified.
The condition occurs primarily in tropical regions and is caused by the injection of a venom or irritant into the human body. The Calabar bean (Physostigma venenosum), a legume native to West Africa, is one of the main sources of this venom. The bean contains toxins, such as physostigmine and eserine, which act as powerful parasympathomimetics and affect the normal functioning of the nervous system.
When an individual is exposed to the venom, either by being bitten or stung, it leads to the development of Calabar bean swellings. These swellings typically appear within hours or days after the initial contact and are characterized by their non-inflammatory nature, meaning they do not exhibit typical signs of inflammation like redness, heat, or pain. Instead, the affected area becomes edematous and swollen, often with a palpable lump beneath the skin.
While Calabar swellings themselves are relatively harmless and usually resolve spontaneously within a few days, the underlying cause of the swelling indicates the presence of venomous organisms in the area that require medical attention and treatment. Therefore, proper evaluation and management of the underlying cause, including identifying the offending insect or worm, is crucial to prevent potential complications or further incidents.
