Connective tissue diseases generally do not have an exact incubation period, which may be months, years, decades, or even longer. They are usually detected when there are clinical symptoms. 1. Connective tissue disease is not a disease, but a large group of diseases, such as rheumatoid arthritis, lupus erythematosus, dermatomyositis, scleroderma, etc., which belongs to the category of autoimmune diseases. 2. The incubation period of connective tissue disease is very long, and there is no exact incubation time to refer to, it may be a few months, a few years, ten years, or even longer. It is usually detected when the patient develops clinical symptoms. 3. Years before the onset of connective tissue disease, the patient’s autoimmune system has already begun to be disrupted, and since connective tissue disease often has no specific symptoms in the early stages, it is also easy to delay the diagnosis. Once connective tissue disease is detected, it is recommended to go to the rheumatology and immunology department of a regular hospital as soon as possible for diagnosis and treatment.