What is a common sign of an allergic reaction?

Itching is a common sign of an allergic reaction because it typically occurs as a result of the body’s immune response to an allergen. When a person is exposed to something they are allergic to, such as pollen, pet dander, or certain foods, their immune system releases histamines and other chemicals. These substances can irritate the skin and lead to symptoms like hives, rashes, or widespread itching. This response is part of the body’s attempt to fight off what it mistakenly identifies as a harmful substance.

In contrast, while weight gain, joint pain, and fatigue can be associated with various medical conditions, they are not specific indicators of an allergic reaction. Weight gain could stem from lifestyle factors or certain medical conditions, joint pain might arise from arthritis or injury, and fatigue could be linked to numerous health issues, including stress, sleep disorders, or chronic illness. Therefore, itching stands out as a direct and indicative symptom of an allergic reaction, distinguishing it from these other symptoms.