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A 24-year-old woman comes to your office to discuss hair loss that began several months ago. She initially noticed a small patch of hair missing near the top of her scalp, but then found several other round patches of loss. These areas are not painful or itchy. She has noticed little "dents" in her nails recently. She is very concerned that she will lose all of her hair.

  • What additional questions would you ask to learn more about her hair loss?
  • How do you classify hair loss?
  • How can you make a definitive diagnosis through an open-ended history followed by focused questions?
  • How does the patient history distinguish between nonpermanent (nonscarring) hair loss and permanent (scarring) hair loss that requires timely intervention?

Hair loss affects nearly 50% of people throughout their lives and often has a profound psychosocial impact.1,2 Hair loss may be due to primary disease of the hair follicle, systemic disease, hormonal changes, or vitamin deficiencies. A careful history may provide the diagnosis and will often guide a directed physical examination and laboratory testing. The history should be guided by a consideration of the patient's demographics and the characteristics of the hair loss.

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Nonscarring (noncicatricial) alopeciaPotentially reversible causes of hair loss.
Scarring (cicatricial) alopeciaIrreversible hair loss associated with destruction of the stem-cell reservoir in the middle of the follicle.
Alopecia areata (AA)An inflammatory process around the follicle that causes isolated or recurrent patches of hair loss.
Telogen effluvium (TE)The most common type of diffuse hair loss, often triggered by a physically or emotionally stressful event 3–6 months before diffuse shedding begins.
Androgenetic alopecia (AGA)The pattern of hair thinning and loss related to hormones, aging, and genetics.
TrichotillomaniaA condition characterized by the compulsion to pull out one's hair.
Central centrifugal cicatricial alopecia (CCCA)A scarring alopecia, most common in African American females, that begins at the vertex of the scalp and progresses outward.

There are 2 principal types of hair loss: those associated with hair follicle destruction and those where the follicle is preserved. Alopecia with destruction of the hair follicle is referred to as "scarring" alopecia, whereas alopecia with preserved follicles is "nonscarring." This is an important distinction because scarring and nonscarring alopecias have different differential diagnoses and prognoses. Scarring alopecias necessitate early intervention in order to minimize the amount of permanent hair loss. Nonscarring alopecias are more common than scarring ones, but the prevalence of specific types of alopecias varies with age.

In children, tinea capitis and alopecia areata are the most common causes, followed by telogen effluvium and trichotillomania. Tinea capitis occurs in 4% to 13% of the general population of children; it is very rarely observed in adults.3–5 Alopecia areata may develop in both children and adults and has a lifetime prevalence of 1% to 2%.2,...

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