**1. Introduction**

Hair loss in children is a common and important complaint in dermatology and pediatric clinics and can be considered as a difficult and challenging problem in some cases. This problem of irreversible hair loss can be a worrying one for parents and kids. In addition, the diagnosis may be a challenge for the doctors to reach a proper diagnosis and therapy for their patients. Early management is needed as this has its effect on development of normal mental and physical growth of children.

Alopecia or hair loss is of particular concern in a pediatric group, as it is associated with more significant psychological consequences in this growing age group and has patterns that are different from that seen in adults.

Similar to hair loss in adults [1], this problem can be caused by a number of conditions, but in patterns that are different in frequencies and presentations from those seen in adults. There are common and uncommon causes for this complaint, and this usually covers a broad differential diagnosis [2]. This chapter has been written in an attempt to distinguish the types of hair loss (acquired and congenital, common and uncommon), to facilitate the diagnostic causes of this problem, and finally to reach a proper treatment.
