Clinical manifestations 1. Most of them have subacute onset, with amorphous fever or normal temperature, heavy cough, initially irritating dry cough, often with sore throat, headache and other symptoms. 2. Multi-system and multi-organ damage may occur, with skin and mucous membrane manifesting as measles-like or scarlet fever-like rash; non-specific myalgia and wandering arthralgia are occasionally seen; cardiovascular system and nervous system damage, hematuria and hemolytic anemia are also manifested. 3. Systemic symptoms are more obvious than chest signs. Physical examination pulmonary signs are not obvious, occasionally slightly low breath sounds and a little dry and wet dumplings. The duration of the disease varies from 2 to 3 weeks, and the complete disappearance of the X-ray shadow extends for 2 to 3 weeks longer than the fading of symptoms, and occasionally extends to 6 weeks. 2.White blood cell count is mostly normal or decreasing, accompanied by increased sedimentation. 3, positive serum cold agglutination reaction, titer >1s128 has diagnostic significance, 50% to 60% of children with positive condensation set test, titer >1s32 can be used as an auxiliary diagnosis. 4, positive serum antibody test, titer >1s160 has diagnostic significance. 5, positive culture of mycoplasma is the gold standard for diagnosis, but the experimental requirements are high, and it is difficult for general laboratories to carry out. Treatment 1, symptomatic treatment Antipyretic, oxygen therapy, nebulization, rehydration, sedation. 2, antibiotic treatment The preferred macrolides, the course of treatment is generally not less than 2 to 3 weeks, stop the drug too early easy to relapse. (1)Azithromycin Dissolve in 5% glucose solution and give it in a sedative drip. (2) Erythromycin Dissolve in 5% glucose solution as an IV. 3. Treatment of extra-pulmonary complications Symptomatic supportive therapy.