The testicles are wrapped inside the scrotum, therefore a hard little meatball grows on the testicles. On the one hand, it may be folliculitis caused by improper cleaning of the scrotal surface, or a local lump after a mosquito bite. On the other hand, sexually transmitted diseases as well as testicular or epididymal diseases can also cause the above symptoms: 1. Folliculitis: Since the scrotum is located in the intimate part of the body and wrapped inside clothing for a long time, it is easy to clean improperly causing bacterial growth and infection, causing local folliculitis. It is generally manifested as red, swollen, painful hard nodules, with the development of the disease can appear pus, softening, breaking caused by severe pain or infection. It is recommended that patients maintain local hygiene, through the application of mupirocin ointment, clindamycin gel and other medications, for the presence of septic conditions, may need to be incised and drained; 2, mosquito bites: dirty environment or summer heat often mosquitoes and insects, due to the hot weather so that patients are generally dressed cool, it is easy to be mosquito bites. Mosquito bites often release toxic anthranilic acid or other saliva substances, causing the body’s immune response, causing local epidermal lumps, shaped like hard meatballs, while accompanied by itching. The actual fact is that you can find a lot of people who are not able to get a good deal on a lot of things. The symptoms are often transmitted through sexual intercourse, and patients should go to the hospital in time to actively treat the cause and avoid spreading it to others; 4, testicular infection: commonly caused by bacteria, mycoplasma, chlamydia and other infections, may also be related to sexually transmitted diseases. The main manifestation is pain and enlargement in the unilateral scrotum, while chronic orchitis is diffusely enlarged and hard in texture, so it is observed from the skin surface like a local growth of hard meatballs. Testicular inflammation may also cause inflammatory polyps in the testicles, which require further diagnosis and treatment. Due to the different causative organisms, there are certain treatment differences in orchitis. Anti-infection treatment with antibiotics, such as cephalosporin and erythromycin, is needed according to medical prescription; 5. Epididymitis: often associated with bacterial infection, sexual transmission, trauma and many other factors. Acute epididymitis is manifested as swelling, pain and limited activity of one side of the scrotum, while chronic epididymitis may cause hard nodules without pressure and pain as the condition develops or the disease lengthens. Suitable antibiotics such as cephalosporins, macrolides and quinolones can be selected for treatment according to the results of bacterial culture and drug sensitivity test. 6. Epididymal cyst: It is often related to blockage of vas deferens, chronic infection of epididymis or testis, trauma and other factors, often manifesting as painless or slight pain, swelling and discomfort in the epididymis or scrotum, and round lumps can be palpated. However, if the pain is obvious or accompanied by other symptoms, it is recommended to actively seek medical advice and perform surgical treatment, while ibuprofen and acetaminophen can be given to relieve the pain symptoms; 7. When the effusion is small, there is no obvious symptom, but with the increase of effusion, scrotal mass and painful tugging may appear. The treatment should be based on the specific condition of the testicular syringomyelia, the patient’s age, and so on, and the doctor will assess whether to choose conservative treatment or surgery; 8, testicular tuberculosis: patients often have a history of tuberculosis, in addition to general weakness, low fever, can be accompanied by testicular enlargement, pain, and occasionally the presence of nodules. Treatment is based on anti-tuberculosis, while if the testicular lesion is serious and even necrosis exists, surgical excision treatment is required. Patients with testicular disease may require surgical drainage, decompression or removal of the diseased tissue in addition to antibacterial treatment, so patients are advised to seek medical attention in a timely manner to avoid further development of the disease.