TELOGEN EFFLUVIUM
This is a common type of temporary hair loss and may occur at any age. The phenomenon represents a precipitous shift of a percentage of anagen hairs to telogen, typically 3 to 4 months after an inciting event. The reaction can be to a variety of physical or emotional stresses:
Etiologies of Telogen Effluvium
Endocrine
Post-partum
Post or peri-menopausal state
Hypo or hyperthyroidism
Nutritional
Caloric or protein deprivation
Zinc deficiency
Biotin deficiency
Iron deficiency
Drugs
Anticoagulants
Angiotensin-converting enzyme inhibitors
Chemotherapeutic agents
Beta blockers
Lithium
Oral contraceptives
Retinoids (e.g. Accutane)
Hypervitaminosis A
Physical stress
Anemia
Systemic illness
Surgery
High fevers
Psychological stress
In a significant number of patients, no obvious cause is found for the telogen effluvium. Telogen effluvium is always potentially completely reversible and does not lead to total scalp loss. Rarely does more than 50% of the hair become involved in a telogen effluvium. For more details on telogen effluvium, please refer to the article found in the Journal Articles on this website.
ANAGEN EFFLUVIUM
The daily loss of some telogen hairs is entirely normal. It is always abnormal to shed anagen hairs. The term anagen effluvium, used to describe the pathologic loss of anagen hairs, is misleading, as the abnormal anagen hairs in this condition are usually broken off rather than shed. An anagen effluvium is an acute, extreme alteration of growth of the majority of anagen follicles, resulting in acute loss of greater than 89-90% of the scalp hair. The hair is usually dystrophic because of the interruption of growth and break off at the level of the scalp. Unlike the shed telogen hair, the anagen effluvium hair lost does not have an attached bulb. These sheds occur 1-2 weeks following the precipitating cause and result in an acute, extensive alopecia that can involve 80-90% of the scalp hair.
The classic and easily recognizable causes of anagen effluvium of the scalp are radiation therapy to the head and systemic chemotherapy, especially with alkylating agents. In addition, there are a large number of toxic chemicals known to cause anagen effluvium such as poisoning by thallium, mercury or borates. Salts of lead, selenium and arsenic have also been incriminated.
Regrowth of hair can usually be anticipated if the precipitating agent is discontinued or removed. Regrowth after radiation therapy depends on type, depth and dose fractionation. The amount of regrowth is directly related to the amount of damage inflicted upon the hair follicles.