Denny, who is allergic to wool, accidentally wears a scarf that is 50% wool. one hour later, after removing the scarf, she finds that the skin around her neck is red and swollen. Explain what has happened to her. (Our unit is Blood and immunity)
Denny's allergic reaction is a result of her contact with wool, which she is allergic to. When Denny wore the scarf, which contained 50% wool, her skin came into direct contact with the wool fibers.
Upon contact, Denny's immune system recognized the wool as a foreign substance and initiated an immune response. In individuals with wool allergies, their immune system perceives wool as a threat and produces specific antibodies called immunoglobulin E (IgE) against wool proteins.
When Denny's immune system encounters wool proteins, the IgE antibodies bind to them, triggering the release of chemicals such as histamine from specialized cells called mast cells. Histamine, along with other chemicals, causes blood vessels in the skin to dilate (widen) and become more permeable.
The dilation of blood vessels leads to increased blood flow to the affected area, resulting in redness and warmth. At the same time, increased permeability allows fluids to leak out of the blood vessels and into the surrounding tissues, causing swelling.
This immune response aims to protect the body from potentially harmful substances. However, in the case of an allergy, the immune system overreacts and causes inflammation and discomfort. In Denny's case, the redness and swelling around her neck are classic signs of an allergic reaction to wool.