Detailed answer

A rash refers to a change in the appearance or texture of the skin, which can occur due to various causes such as allergies, infections, or irritants. It can present as redness, itching, bumps, or blisters on the skin. On the other hand, a sinus infection, also known as sinusitis, is an inflammation of the sinus cavities caused by a viral, bacterial, or fungal infection. It commonly manifests as facial pain, sinus pressure, nasal congestion, thick nasal discharge, and sometimes a persistent cough. While a rash primarily affects the skin, a sinus infection primarily affects the nasal passages and sinuses. It is important to consult a healthcare professional for an accurate diagnosis and appropriate treatment for either condition.