A red, swollen mass under the right eye of a 9-year-old boy may be caused by blepharitis and folliculitis. 1. Blepharitis: Blepharitis is an acute purulent inflammation of the eyelid glands, mostly caused by staphylococcal infections. When the patient is infected by the bacteria, the patient’s eyelid may appear localized abscess, often accompanied by redness, swelling, pain and other uncomfortable symptoms. 2. Folliculitis: Folliculitis is an inflammation caused by Staphylococcus aureus infection of the hair follicle, the main symptom of the patient is a single or multiple hair follicle-centered red papules, accompanied by localized pain, swelling and other discomforts of the eyelid, and so the patient’s eyelids may appear congested and elevated swelling. It is recommended that children with significant redness and swelling of the eyelids be seen promptly for evaluation of the condition and treatment as prescribed by the physician.