Telogen effluvium (TE) is heterogeneous disorder. It can be classified into three main categories: the premature teloptosis, the collective teloptosis and the premature entry into telogen. The last category can be divided in three types: the drug induced TE, TE due to dietary deficiencies and the "autoimmune" TE. Despite this heterogeneity, the large majority of TE that arrive at the dermatologist's observation pertain to the autoimmune type, featuring a standard presentation. The typical patient is a woman claiming to have always had a "full head of hair" and reporting her hair to come out suddenly "by the handful". Usually, she is accurate about the date of onset of her shedding. She is in good health, without signs of anorexia nor nutrient deficiencies. She admits to having been in an anxious state for some months, and felt, occasionally or not, a painful or burning sensation at the scalp (trichodynia). Usually, the course of the disorder is chronic but intermittent, with apparent remissions being irregularly intermitted by relapses. The shed hairs do not exhibit telogen roots, but mostly exogen ones. This distinct entity, shares some analogies with alopecia areata, including the triggering role of emotional stress, trichodynia and the frequent association with Hashimoto's thyroiditis. Methods to assess its severity and to monitor treatment are described. In the absence of a documented etiopathogenesis, no treatment can be endorsed, but a course of topical corticosteroids could be tried.