Article in English: Several medical conditions can either temporarily or permanently interfere with normal hair growth and development. Some of these medical conditions include the following:  Iron deficiency anemia.  Thyroid conditions.  Deficiencies in zinc, vitamin D, and possibly the B vitamin group.  Hormonal level alterations of androgen, testosterone, and estrogen-derived hormones.  Autoimmune disease.  Major psychological stress.  Physical trauma.  Scalp infections and skin disorders.  Diabetes.  Lupus.  Trichotillomania.  Stress Postpartum hair loss Extreme weight loss, or extreme change in diet.  Severe infection accompanied by a high fever. Medical conditions can lead to either temporary or permanent problems with hair loss.  With the help of your doctor, and possibly healthcare professionals that practice in specialty areas, treating the underlying medical condition may resolve your hair loss problem.  Your doctor will need as much information as possible about your hair loss problem, so be prepared to discuss this issue in depth. Be prepared to describe when it began, any significant life events that occurred just prior to the problem, steps you have taken to resolve it, and how much distress the hair loss is causing you.  If an underlying medical condition is discovered, specialists that may be part of your treatment may include endocrinologists, dermatologists, nutritionists, and psychiatrists. Many of the medical conditions listed interfere with one of the three phases of hair growth.  The anagen phase is the period when your hair is actively growing. About 85% of your hair is in the anagen, or growing phase, at any given time.  The catagen phase is a short period of time, about two weeks in durations, that allows the follicle to regenerate. Hair growth is halted during the catagen phase.  The telogen phase is considered the resting phase of hair growth, and lasts for two to four months. At the end of this phase the hair falls out. Most people normally lose about 100 hairs each day due to the hair that is in the...

Summary in Chinese:
就医检查，排除疾病因素。 治疗疾病。 了解头发生长周期。 休止期脱发通常很短暂。 让医生检查你目前服用的药物。 考虑基因的影响。 了解激素变化造成的脱发。 检视你的饮食。 了解年龄增长会引起脱发。