Dry syndrome (SS) is a chronic inflammatory autoimmune disease mainly involving exocrine glands, also known as autoimmune exocrine gland epithelial cellitis or autoimmune exocrinopathy. Primary dry syndrome is a global disease, the prevalence of which is 0.3%~0.7% in our population, and 3%~4% in the elderly population. The disease is more common in women, the ratio of men to women is 1:9～20. The age of onset is mostly 40～50 years old. It is also seen in children. Local manifestation (1) Dry mouth: Due to salivary gland lesion, the lack of salivary mucin causes the following common symptoms: ① Most patients complain of dry mouth, and in serious cases, the oral mucosa, teeth and tongue become sticky, so that they need to drink water frequently when they talk, and when they eat solid food, they need to send down with water or liquid food. ②Rampant dental caries is one of the characteristics of this disease. About 50 patients have multiple carious teeth with uncontrollable development, manifested as gradual blackening of teeth, followed by small pieces falling off, and finally only the residual roots remain. (iii) In adult mumps, 50 patients present with intermittent alternating parotid swelling and pain, involving unilateral or bilateral. Most of them subside on their own in about 10 days, but sometimes the swelling persists. A few have submandibular gland enlargement, and less frequently sublingual gland enlargement. ④The tongue shows painful tongue, dry and cracked tongue, and atrophied and smooth tongue papillae. ⑤ The oral mucosa shows ulcers or secondary infection. (2) Dry keratoconjunctivitis: This is due to the decrease of mucin secreted by the lacrimal glands and presents with symptoms such as dry eyes, foreign body sensation, few tears, and in severe cases, painful crying without tears. Some patients have recurrent purulent infection of the eyelid margin, conjunctivitis, keratitis, etc. (3) Other: superficial areas such as nose, hard palate, trachea and its branches, digestive tract mucosa, and exocrine glands of vaginal mucosa can be involved, resulting in less secretion and corresponding symptoms. 2. Systemic manifestations In addition to dry mouth and eyes, patients may also have systemic symptoms, such as weakness and low fever. About 2/3 of patients have systemic damage. (1) Skin: Allergic purpura-like rash may appear, mostly on the lower limbs, as red papules with clear borders of the size of rice grains, which do not fade when pressed and appear in batches. The duration of each batch is about 10 days, and it can fade on its own with brown pigmentation. (2) Joints: arthralgia is more common, and most of them do not show any destruction of joint structures. (3) Kidney: About half of the patients have renal damage, mainly involving the distal tubules, and may develop renal tubular acidosis. A small percentage of patients show more obvious glomerular damage, with clinical manifestations of massive proteinuria, hypoalbuminemia, and even renal insufficiency. (4) Lung: Most patients have no respiratory symptoms. Those with mild involvement present with dry cough and those with severe involvement present with shortness of breath. The main pathology of the lungs is interstitial lesions, and another small percentage of patients develop pulmonary hypertension. Those with pulmonary fibrosis and severe pulmonary hypertension have a poor prognosis. (5) Digestive system: non-specific symptoms such as atrophic gastritis, decreased gastric acid and dyspepsia may occur, and patients may have liver damage. (6) Nervous system: A few patients are involved in the nervous system. Peripheral nerve damage is the most common. (7) Hematologic system: The disease may present with reduced white blood cell count or (and) thrombocytopenia, and bleeding may occur in severe cases of low platelets. The incidence of lymphoma in this disease is much higher than in the normal population.