Whilst the condition does not exclusively occur amongst tennis players, they are most vulnerable to the condition. Tennis elbow specifically affects the wrist flexors and pronators that are attached to the medial epicondyle.

• Overuse: repetitive use of a muscle in the forearm can cause microscopic tears to occur in the tendon, this can lead to inflammation, also known as tendonitis. 
• Holding or hitting heavy objects: holding something that is heavy or hitting heavy objects such as a wet tennis ball can cause tennis elbow.
• Acute trauma: an accident or high-impact object hitting the elbow leading to violent contraction of the muscle, can result in tennis elbow. 
• Poor body mechanics: incorrect movement of the body can cause an overexertion or strain on the muscles and tendons of the forearms, leading to tennis elbow.

• Discomfort or pain in the elbow at all times 
• Pain when extending your wrist or gripping objects 
• Pain when twisting your arm 
• Pain when extending or bending your arm 
• Swollen or slight enlargement of the elbow region 

A tennis elbow could resolve by itself provided that you rest sufficiently. However if left unresolved, it could lead to the onset of osteoarthritis. 

• Athletes and hobbyists: certain activities like racket sports and throwing sports that put excessive pressure on the forearm will increase your risk of developing tennis elbow.
• Manual workers: jobs such as plumbers, carpenters, and construction workers whose work is labour-intensive and involves the usage of tools can increase the risk of tennis elbow. 
• Age: adults within the age range of 30-50 are at an increased risk because muscle strength tends to reduce at this age. Additionally, the reduced collagen production is also suspected to be the cause. 

Diagnosis of tennis elbow may involve the following: 

• Physical examination: by physically examining your range of motion and tenderness of the area,  an orthopaedist would be able to gauge the severity of your condition. 
• X-ray: if your orthopaedist suspects there may be an incidence of fracture or presentation of arthritis, you would be advised to undergo an x-ray. 
• Electromyography (EMG): this would be necessary if your orthopaedist suspects impinged nerve occurrence.

• Medication: given that tendonitis is fundamentally an inflammation issue, oral medications (NSAIDs) are commonly prescribed as the first course of treatment.
• Physiotherapy: physiotherapy involves gentle and therapeutic exercises that help to improve the range of motion and improve the strength of weak muscles.
• Surgery: in rare cases, tennis elbow repair may be advised in which damaged tendons are scraped away.