What would cause a red ring around the elbow?

A red ring around the elbow can be caused by several factors, including skin conditions like eczema, psoriasis, or ringworm. It may also result from an allergic reaction to products such as soaps, lotions, or fabrics. In some cases, it could indicate an infection or inflammatory condition, so monitoring for additional symptoms is important. If the ring persists or worsens, consulting a healthcare professional is advisable.