Your roommate is rushed to the hospital after suffering a severe allergic reaction to a bee sting. After she is treated and released, she asks you (the local biology expert!) to explain what happened. She says, 'I don't understand how this could have happened. I've been stung by bees before and didn't have a reaction.' Suggest an explanation for what has happened to cause her severe allergic reaction and why she did not have the reaction after previous bee stings.

Verified step by step guidance

1. Understand that allergic reactions are caused by the immune system responding to a perceived threat. In the case of bee stings, the venom contains proteins that can trigger this response.
2. Recognize that sensitization is a key factor. The first time or initial times your roommate was stung by a bee, her immune system was exposed to the venom and began creating specific antibodies (IgE) against the venom proteins.
3. Explain that upon subsequent exposure to the same allergen (bee venom), these IgE antibodies recognize the venom proteins and bind to them. This binding triggers immune cells called mast cells to release histamine and other chemicals, leading to the symptoms of an allergic reaction.
4. Discuss how the severity of allergic reactions can vary. It's possible that during previous stings, the immune response was not strong enough to cause noticeable symptoms, but with repeated exposure, the immune system's response can become more aggressive, leading to a severe reaction.
5. Suggest that individual factors such as changes in health, medication, or even the amount of venom injected can influence the severity of an allergic reaction. It's important for her to consult with a healthcare provider to discuss potential allergies and consider carrying an epinephrine auto-injector in case of future stings.