Final answer:
A rash on the forearm can have various causes including allergies, infections, and skin conditions.
Step-by-step explanation:
A rash on the forearm can be caused by various factors such as allergies, infections, or skin conditions. Allergic reactions to certain substances like plants, cosmetics, or metals can result in a rash. Infections caused by bacteria, fungi, or viruses can also lead to a rash. Additionally, skin conditions like eczema or psoriasis can manifest as a rash on the forearm.
Learn more about Causes of a rash on the forearm