Hematoglobin nevus mainly refers to bright red nevus, which is a disease caused by vascular malformation, mainly leading to skin symptoms or neurological symptoms, and will not cause coughing, and if coughing occurs, it needs to be clarified whether there are other diseases. Nevus erythematosus is a disease caused by abnormal expansion of capillaries, which is a congenital disease, often occurring in the face and neck, scalp and other parts. It manifests as single or several red patches on the skin, and the color will fade when pressed locally, and capillary dilatation can be seen; some people will also have neurological symptoms, such as eye twitching on the side of the erythema, and so on. The disease mainly causes skin changes and does not cause coughing. If a cough develops, it is important to consult a physician to determine the cause. It may be caused by non-disease or disease factors, common non-disease factors include exposure to substances that irritate the throat, eating too fast, etc. Disease factors include a variety of respiratory diseases, circulatory diseases such as mitral stenosis, and neurological symptoms such as encephalitis. It is recommended that after the appearance of nevus erythematosus, timely consult the doctor for relevant formal treatment; if coughing occurs at the same time, it is necessary to carry out other examinations to clarify the specific causes of the disease.