A high CRP level can be caused by various factors. Infections, such as bacterial, viral, or fungal infections, can trigger an inflammatory response and elevate CRP levels. Additionally, autoimmune diseases like rheumatoid arthritis or lupus can lead to chronic inflammation and elevated CRP. Other causes include tissue injury, certain cancers, inflammatory bowel disease, and cardiovascular conditions. Lifestyle factors like obesity and smoking can also contribute to increased CRP levels. It is important to note that CRP alone is not specific to any particular condition, so further evaluation is necessary to determine the underlying cause of the elevated CRP.