Nodular disease is a granulomatous disease that can involve all systems of the body and is characterized by non-caseating necrotizing granulomas; it is not a neoplastic disease. The chest, including the lungs, mediastinum, and hilar lymph nodes, is the best site for nodular disease, followed by the skin and eyes. In addition, the liver, superficial lymph nodes, heart, kidneys, pulmonary vessels, bones, spleen, and other tissues and organs can be involved. Most of the nodules are detected during routine chest radiography, but some patients may have respiratory symptoms such as coughing and wheezing, often accompanied by fatigue, weight loss, and hypothermia. 25% of patients with nodular disease have skin involvement, mainly in the form of erythema nodosum and frostbite rash, but also in the form of maculopapular rash, hyperpigmentation, skin ulcers, psoriasis-like lesions, and scarring alopecia. skin lesions, scarring alopecia, skin atrophy, etc. Typical erythema nodosum presents as painless, erythematous raised skin lesions, mostly on the extensor side of the lower extremities. Lupus-like lesions, on the other hand, are commonly seen in chronic progressive nodular disease, mostly located on the cheeks, nose, lips and ears. Nodular disease is highly prevalent in the female population aged 30 to 55 years. The etiology and pathogenesis of nodular disease are unknown and may be related to infection by certain pathogens, environmental factors, etc. Nodular disease is not an infectious disease or a genetic disease, but people with certain susceptible genetic backgrounds may be susceptible to nodular disease in response to external environmental factors. Studies have found that about 2/3 of patients with nodular disease heal spontaneously, about 1/3 require treatment, and about 5% may suffer irreversible damage to vital organs or even die despite aggressive treatment. Not all patients with nodular disease require treatment. Patients with nodular disease with significant organ involvement need to receive drug therapy, such as patients with pulmonary nodular disease with severe pulmonary involvement and/or significant clinical manifestations, patients with nodular disease with cardiovascular involvement, patients with hepatic nodular disease, patients with renal nodular disease, and patients with ocular nodular disease. Patients with nodular disease are prone to relapse, especially those who have improved after treatment, but usually relapse within 2 years of stopping treatment. Regular outpatient follow-up is recommended after stopping treatment, at least once every six months. In patients with spontaneous remission, the recurrence rate is much lower than in patients with treated nodules. Nodular disease is a granulomatous disease and does not become malignant. However, due to the immune dysfunction of patients with nodular disease, some patients with nodular disease may be combined with certain malignant neoplastic diseases.