Chemotherapy induced hair loss / Anagen effluvium

Overview:

Anagen effluvium is a form of nonscarring hair loss commonly associated with chemotherapy. In this disorder, affected hairs in the growth phase (anagen hairs) suffer a toxic or inflammatory insult, resulting in fracture of the hair shaft. Anagen effluvium is often referred to as chemotherapy-induced alopecia, as it can be triggered by antimetabolites, alkylating agents, and mitotic inhibitors administered as chemotherapeutic therapy. Shedding usually takes place within 14 days of administration of the offending drug, however, in many instances it is reversible, with hair regrowth growth upon discontinuation of the offending agent. In this article we will be reviewing causes, symptoms, diagnosis, treatment, and prognosis of anagen effluvium.

Causes:

Anagen effluvium is often referred to as chemotherapy-induced alopecia, as it can be triggered by antimetabolites, alkylating agents, and mitotic inhibitors administered as chemotherapeutic therapy. To understand anagen effluvium, you must first comprehend the cyclical phases of hair growth and how the hair follicle functions. The human scalp contains around 100,000 hairs at any given time; each individual hair follicle goes through three stages of growth: anagen, catagen, and telogen. Approximately 90% of hairs taken from a normal scalp are in the growth (angen) phase, which lasts between 2 and 6 years with an average of 3 years. This is a period of proliferation, in which hair matrix cells undergo mitosis and proliferation to form the hair shaft. Insult to the hair hair matrix in the form of medications, toxin exposure, or inflammation can cause a cessation of this mitotic activity and damage to the hair shaft resulting in breakage, and if the bulb is affected, complete hair loss.

Symptoms:

Anagen effluvium typically affects the scalp, but it can also affect other parts of the body where hair is growing, such as the eyebrows, eyelashes, and pubic area. The hair loss is often diffuse, meaning it affects a large area of the scalp or body. Similar to telogen effluvium, hair tends to come out diffusely in clumps in the shower or with brushing.

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Diagnosis:

Anagen effluvium is diagnosed by taking a medical history and performing a physical examination.  Patients will report sudden diffuse hair loss typically after starting a new medication. A skin biopsy may also be performed to rule out other causes of hair loss.

Treatment:

There is no specific treatment for anagen effluvium, as the hair loss is typically reversible once the underlying cause is resolved. In most cases, hair regrowth will occur within a few months after discontinuation of the offending agent. If the hair loss is severe, however, some patients may require treatment with minoxidil (oral or topical). There are some devices that help him limit anagen effluvium including a cold cap that reduces blood flow to the scalp during chemotherapy administration.

Prognosis:

The prognosis for anagen effluvium is generally good, as the hair loss is typically reversible. In most cases, hair regrowth will occur within a few months after discontinuation of the offending agent. Hair may be thinner after it regrows in which case minoxidil may help with length and hair thickness. However, in some cases, anagen effluvium can lead to permanent hair loss.