Telogen Effluvium

Etiology

Telogen effluvium is a reactive process triggered by metabolic stress, hormonal changes, or medications. Common triggering events include acute febrile illness; severe infection;[7] major surgery; severe trauma; postpartum hormonal changes, particularly a decrease in estrogen; hypothyroidism;[8] sudden discontinuation of estrogen-containing medications; crash dieting; low protein intake; heavy metal ingestion; and iron deficiency. Many medications have been linked to telogen effluvium, but the most common are beta-blockers; retinoids, including excess vitamin A; anticoagulants; propylthiouracil; carbamazepine; and immunizations.[9]

Epidemiology

Telogen effluvium is a condition that can affect individuals of any age, gender, or racial background. The exact prevalence of telogen effluvium is unknown, but it is considered quite common. Many adults experience an episode of telogen effluvium at some point in their lifetime.[10] Although telogen effluvium can manifest in both men and women, women tend to be more susceptible because of postpartum hormonal changes. In addition, women are more disturbed by hair shedding compared to men and are more likely to seek medical attention.[11][12][13][14]

Pathophysiology

Telogen effluvium is triggered when physiologic stress causes a large number of hairs in the growing phase (anagen phase) of the hair cycle to abruptly enter the resting phase (telogen phase). During this phase, the growth of the telogen hairs ceases for 1 to 6 months (on average 3 months), though the patient does not notice this cessation of growth. When the affected hairs re-enter the growth phase (anagen phase), the hair strands that had been suspended in the resting phase (telogen) are extruded from the follicle, resulting in noticeable hair shedding.

At a molecular level, etiological factors may disturb the intricate balance of growth factors, neuroendocrine signals, and cytokine involvement in follicular homeostasis. This disturbance can lead to premature catagen induction or prolongation, accelerating the transition of hairs into the telogen phase.

Pertinent research in recent years suggests the involvement of inflammatory mediators, oxidative stress, and changes in the microenvironment of the hair follicle niche in perpetuating telogen effluvium. The involvement of multiple pathways indicates the complexity of telogen effluvium's pathophysiology and provides potential targets for efficient diagnosis and therapeutic intervention.[15]

Histopathology

Histological findings in telogen effluvium are best observed with transverse sections of a punch biopsy. The number and density of hair follicles are typically normal, but there is an increased percentage of hair follicles in the catagen or the telogen phase.[15] If at least 25% but not more than 50% of the follicles are in the telogen phase, the diagnosis of telogen effluvium is confirmed.

History and Physical

Patients typically present with hair shedding, usually without other symptoms and with a relatively abrupt onset. By definition, the shedding in acute telogen effluvium lasts less than 6 months; often, the shedding period is much shorter. Obtaining a thorough history can reveal a causative event (refer to the list in the Etiology section for the conditions that may be considered) occurring approximately 3 months before the onset of the shedding. However, this timeframe could range from 1 to 6 months. Frequently, the patient may have completely recovered from the acute illness or identifiable incident and may not recognize the connection with the hair loss.[16]

The physical examination is grossly normal, as it is difficult for the casual observer to appreciate the volume of hair loss. Comparing the patient's current appearance with old pictures can be beneficial (see Image. Telogen Effluvium in a Patient After Prolonged Crash Diet). If the patient presents during the acute shedding, a gentle pull test results in the removal of at least four hairs with each pull. However, if the patient presents after the acute shedding has passed, the pull test may yield normal results. A thorough examination of the scalp may reveal an increased percentage of short anagen hairs growing close to the scalp, and no scarring should be evident.

Evaluation

Typically, obtaining a detailed history and performing a thorough physical examination are sufficient for diagnosing telogen effluvium. If a biopsy is performed during the acute shedding phase (when the pull test is positive), it can confirm an increase in the percentage of telogen hairs.[15] Testing for underlying hormonal conditions, such as hypothyroidism; chronic metabolic illnesses; or iron deficiency is recommended if there are concerns about these conditions.[17][18]

Laboratory Testing

Hypothyroidism

• Hypothyroidism can lead to chronic telogen effluvium.
• When symptoms of hypothyroidism, such as tiredness, constipation, weight gain, and cold sensitivity, are present, a thyrotropin test is warranted.[19]

Iron deficiency

• Iron deficiency should be evaluated with a complete blood count, serum iron, iron saturation, and ferritin. [20]
• Given the priority of blood for survival over hair, the body prioritizes shedding hair before red blood cell indices become microcytic.
• Ferritin acts as an acute-phase reactant, and inflammation can result in normal ferritin levels in an iron-deficient individual.
• 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

• When symptoms of syphilis, such as fatigue, patchy hair loss, sore throat, or swollen lymph nodes, are present and considered a cause, a rapid plasma reagin or venereal disease research laboratory (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.
• A white bulb and no gelatinous hair sheath can identify telogen hair.
• 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 24 hours, refraining from washing their hair during this time. This process should be repeated every week for three or four collections.
• Collecting 100 or more hairs in 24 hours suggests telogen effluvium. The number of hairs collected may decrease if the collections are performed over several weeks while the telogen effluvium improves. 

Treatment / Management

Acute telogen effluvium is a self-limited condition. If the causative event has been identified and appropriately treated, there is no need for further treatment. If a hormonal or dietary imbalance, such as low iron levels, zinc levels, vitamin D levels; or metabolic illness is present, hair growth returns after these factors are corrected.[21] If a medication is the cause of the shedding, hair growth restarts after the medication is withdrawn.[22](B3)

Although topical minoxidil has not been proven to promote hair recovery in telogen effluvium, it has theoretical benefits. Patients who wish to take an active role in their treatment may choose to use topical minoxidil. Recent trials have proven that oral minoxidil can be an effective and well-tolerated treatment alternative for healthy patients with difficulty with topical formulations.[23]

Recent studies have also shown that both botulinum toxin A and multivitamin mesotherapy are effective in treating telogen effluvium. These treatments demonstrated improvement of the criteria terminal hair and multiple follicular units.[24] (B2)

Most importantly, all the patients should be offered emotional support and reassurance about the benign course of the disease and the possibility of complete recovery of hair with time and nutritional support. 

Differential Diagnosis

The differential diagnoses of telogen effluvium include alopecia areata, anagen effluvium, androgenetic alopecia, scarring alopecia, syphilis, and trichotillomania.

Prognosis

Morbidity associated with telogen effluvium is typically limited to mild cosmetic changes, and there have been no reports of mortality.

• Telogen effluvium has a significant psychological impact on individuals affected by the disease, and therefore, counseling is required. 
• The prognosis for a good recovery of hair density occurs in acute telogen effluvium.
• A good cosmetic outcome is also expected in chronic telogen effluvium, even if the hair shedding continues.

Complications

Telogen effluvium is a benign and spontaneously reversible condition with no associated complications. As it is a non-cicatricial alopecia, the scalp has no scarring, even during the active hair loss phase.