**13. Treatment**

**11.5. Wood's light examination**

the diagnosis remains unclear [10].

**11.6. Procedures**

134 Hair and Scalp Disorders

**11.7. Scalp biopsy**

separate section [10].

**12. Differential diagnosis**

sis of seborrheic dermatitis, which unveils the scale [32].

edge of the alopecic area and avoid completely bald areas [10].

whereas a more diffuse pattern has also been described [29, 35].

**11.8. Trichograms and phototrichograms**

TE can be due to seborrheic dermatitis of the scalp. On physical examination, a greasy scale and erythema on the scalp can be seen with a characteristic distribution. In addition, examination with a Wood's lamp (a source of ultraviolet A light) can be useful for the definite diagno-

In the majority of cases, further investigation is not required, beyond the clinical history and physical examination. However, additional diagnostic tools can be useful in patients in whom

In most cases, scalp biopsies are not required and are only reserved for certain patients with an obscure diagnosis. Although scalp biopsy is not mandatory, it helps to exclude female pattern hair loss and alopecia areata. In general, biopsy results are normal, except increased telogen follicles (normal telogen counts vary between 6 and 13%). The rate of telogen follicles more than 15% indicates TE, while more than 25% is the major manifestation of TE [2, 30].

A 4-mm punch biopsy is sectioned horizontally for each specimen, and a second specimen is sectioned vertically. In general, we perform biopsy in an area outside of predilection for androgenetic alopecia to reduce the possibility of diagnostic uncertainty; therefore, we avoid bitemporal, frontal, and vertex areas of the scalp, if applicable. We usually select the leading

Although these techniques are less common, they may be helpful to confirm the diagnosis of TE. With the use of these techniques, the rate of telogen and anagen hair follicles on the scalp can be evaluated. Currently, trichograms and phototrichograms are mostly used in specialized clinical hair centers and research studies. These procedures are described in detail in a

The pattern of hair thinning or shedding can be helpful in the differential diagnosis. Diffuse thinning of the scalp hair in both temporal regions is highly suggestive of TE [33]. Frontal fibrosing alopecia almost particularly affects the frontal and frontotemporal hairlines. In case of traction alopecia, the periphery of the scalp is usually affected. Central centrifugal cicatricial alopecia (CCCA) typically begins at the vertex of the scalp, expanding centrifugally [34]. Alopecia areata may present in varying patterns. The patchy type is usually localized, Consulting on the natural course of the disease is the mainstay of the treatment of TE. A detailed evaluation should be performed to identify the underlying cause. In general, hair loss halts within 3–6 months in patients in whom a triggering factor is identified and eliminated [2].

Although spontaneous improvement is expected for patients with TE related to an isolated event such as childbirth, those related to a persisting insult should have the cause eliminated or treated, if applicable. In case of drug-induced TE, the suspected drug should be discontinued for at least 3 months to identify whether hair loss improves with the discontinuation of therapy. In addition, concomitant hair or scalp disorders such as seborrheic dermatitis should be simultaneously treated [10].

Furthermore, hair loss may profoundly affect the psychosocial status of the patient, irrespective of the degree of hair loss. Therefore, emotional well-being of the patient is critical in the management. All concerns of the patient should be sensitively addressed by the clinician. In addition, patients should be educated on the hair growth cycle and the expected course of TE, including an explanation that complete hair loss is not expected to occur, to reassure patients. Follow-up is also helpful both to encourage the patient and to identify those requiring further evaluation for persistent TE [10].

Moreover, the diagnosis and treatment of TE should be briefly discussed with the patient. Potential therapeutic options include the followings, based on the pathogenesis of TE:


Currently, no potent, FDA-approved catagen inhibitors or anagen inducers are commercially available. However, catagen-inducing drugs such as beta-blockers, retinoids, anticoagulants, or antithyroid drugs should be avoided and catagen-inducing endocrine disorders including thyroid dysfunction, hyperandrogenism, or hyperprolactinaemia should be simultaneously treated. Replacement therapy for catagen-promoting deficiencies such as iron, zinc, estradiol, or proteins can be also prescribed [2].

Today, no proven vitamins or supplements for any form of hair loss are commercially available. In case of a measurable deficiency such as iron-deficiency anemia, replacement therapy may be initiated. However, a balanced diet and stable body weight are the critical measures. In the literature, biotin supplementation has been shown no effect on TE [36]. Despite their claimed benefits, there are no controlled studies investigating the efficacy of iron or thyroxine replacement on TE [4]. In addition, maintaining serum ferritin above 40 ng/dL has been suggested to reverse hair loss [26]. In case of poor response, possible factors such as poor compliance, misdiagnosis, malabsorption, coexisting anemia, or persistent blood loss should be considered. Iron supplementation should be continued for 3–6 months, until the iron stores are replenished [37]. Of note, unnecessary long-term iron supplementation may result in iron overload [38]. On the other hand, there is no proven effect of antioxidants or other supplements on TE [39].

#### **14. Conclusion**

In conclusion, TE is a common disease that causes diffuse hair loss. The diagnosis of acute TE is based on patient's history and examination findings. Since acute TE is self-limiting, the clinician should monitor the patient, until spontaneous resolution. However, in case of severe or prolonged shedding, further investigations are warranted. On the other hand, chronic TE can be only diagnosed, after other causes of chronic diffuse telogen hair loss are ruled out. There is no specific treatment for TE. In the management of TE, the major aspect is to educate the patient relating to the natural history of the condition.
