Final answer:
You and your friend are likely experiencing itchiness which can be due to various causes such as infections, allergic reactions, skin conditions, or psychological factors like sympathetic itching.
Step-by-step explanation:
You are experiencing a sensation known as itchiness or pruritus. This sensation can be caused by a variety of conditions, such as allergic reactions, skin infections like ringworm, or contact with irritants like poison ivy. It can also be a symptom of diseases like eczema, psoriasis, or even systemic conditions like Lyme disease. Your friend's rash and the urge to scratch in response to seeing someone else scratch is a phenomenon that may involve a psychological component, often referred to as "sympathetic itching," which is not related to an actual physical stimulus. If the itchiness persists, it is advisable to seek medical attention to determine the cause and appropriate treatment.