Patients will report hair shedding, usually without other symptoms, with a relatively abrupt onset. By definition, in acute telogen effluvium, shedding lasts less than six months; often the period of shedding is much shorter. A careful history will identify a causative event (see etiology section) occurring approximately 3 months before the onset of the shedding (range from 1 to 6 months). Quite often the patient has fully recovered from the acute illness and fails to see the connection between the illness with the hair loss.

The physical examination is grossly normal, as it is difficult for the casual observer to appreciate the loss of hair volume. It can be helpful to compare the patient's current appearance with old pictures. If the patient presents during the acute shedding, a gentle pull test yields at least four hairs removed with each pull. However, if the patient presents after the acute shedding has passed, the pull test may be normal. Careful examination of the scalp will show an increased percentage of short anagen hairs growing close to the scalp.

Usually, a careful history and physical examination are sufficient to diagnose telogen effluvium. Biopsy, if taken during the acute shedding phase (when the pull test is positive), can confirm an increase in the percentage of telogen hairs. If there is a concern for a hormonal condition (such as hypothyroidism), a chronic metabolic illness, or iron deficiency, testing for these conditions is indicated.[10][11]

Laboratory Testing

Chronic telogen effluvium sometimes has a metabolic cause. 

• Hypothyroidism
• If symptoms of hypothyroidism are present, a thyrotropin test is warranted. 

Iron Deficiency

• Iron deficiency should be evaluated with a CBC count, serum iron, iron saturation, and ferritin. 
• Blood is more important to survival than hair, so the body will shed hair before red cell indices become microcytic. 
• Ferritin behaves as an acute phase reactant, and inflammation can result in normal ferritin levels in an individual who is iron deficient. 
• A low ferritin confirms iron deficiency; a normal ferritin level does not exclude iron deficiency. 
• Iron saturation is the most sensitive indicator of iron deficiency.

Syphilis

• If syphilis is considered as a cause, a rapid plasma reagin or VDRL test should be performed.

Biopsy

• Scalp biopsy is the most useful test to confirm the diagnosis, but it is seldom necessary if gentle hair pull produces numerous telogen hairs.
• Telogen hairs can be identified by a white bulb and no gelatinous hair sheath.
• If a patient is unwilling to allow a scalp biopsy, serial hair collections can be obtained. 
• The patient should be instructed to collect all shedding hair in a 24-hour period. The patient should avoid washing the hair during the collection. This process should be repeated every week for a total of 3 or 4 collections.
• Collecting 100 hairs or more hairs in a 24-hour period suggests telogen effluvium. If the collections are performed over several weeks while the telogen effluvium is improving, the number of hairs collected may decrease. 

Acute telogen effluvium is a self-limited condition. If the causative event is identified by history and has been adequately treated, there is no further treatment required. If a hormonal or dietary imbalance or metabolic illness is present, hair growth will return after these factors are corrected. If a medication is the cause of the shedding, hair growth will restart after the medication is withdrawn. 

Hair transplantation has no role in the treatment of telogen effluvium.

While topical minoxidil has not been proven to promote recovery of hair in telogen effluvium, it has theoretical benefit. Patients who wish to take an active role in their treatment may choose to use minoxidil.

The differential diagnoses includes:

• Alopecia Areata
• Anagen Effluvium
• Androgenetic Alopecia
• Scarring Alopecia
• Syphilis
• Trichotillomania

Morbidity is generally limited to mild cosmetic changes which are mild. Mortality has not been reported.

• Telogen effluvium has a major impact on those affected by the disease. 
• Prognosis for a good recovery of hair density occurs acute telogen effluvium.
• A good cosmetic outcome is also expected in chronic telogen effluvium, even if the hair shedding continues.

It may take up to 6 months for hair growth to restart, and even longer for the growth to be appreciable by the patient. Patients often require reassurance of the normal recovery of their hair while the hair reenters anagen and grows normally. Patients may also worry that normal grooming of their hair worsens the hair shedding. Patients should be reassured that their hair is normal and that they can wash and style their hair as usual.

The diagnosis and management of hair loss is with an interprofessional team that includes a dermatologist, primary care provider, nurse practitioner, and an internist. One type of hair loss is Telogen effluvium, which is a form of nonscarring alopecia characterized by diffuse, often acute hair shedding. In most cases, no cause is ever found. In any case, patients need to be educated that the condition is self-limiting. There is no need to prescribe hair growth medications or refer the patient for a hair transplant. The hair growth will return but it may take a few months or even a year. For most patients, the outcome is good. [12][13](Level V)