- Clinical science
Alopecia is the loss of hair from any hair-bearing area of the body, but most often the scalp. It may be congenital or acquired, circumscribed or diffuse, and cicatricial or nonscarring. Androgenetic alopecia, a type of diffuse, nonscarring, acquired alopecia, is the most common, affecting > 70% of the general population by 70 years of age. Alopecia areata, an acquired, circumscribed, nonscarring alopecia, is the next most common type. Clinical diagnosis is usually possible. In ambiguous cases, diagnosis is aided by microscopic examination of the hair, trichograms, and scalp biopsy. Treatment depends on the type of alopecia and includes long-term (at least 1 year) use of topical minoxidil, corticosteroids (topical, intralesional, or oral), or antiandrogens. Surgery (hair transplant) or camouflaging techniques are used when medical therapy fails. The prognosis is variable and depends on the etiology and severity of hair loss.
- Alopecia: : loss of hair (baldness)
- Effluvium : process of hair loss
- Atrichia : inherited hair loss
- Hypotrichosis : congenital sparse hair, which is usually associated with syndromes such as:
- Anagen phase: phase of active growth
- Telogen phase: resting phase
- Catagen phase: phase of follicular regression
|According to etiology (congenital/acquired) and pattern (diffuse/circumscribed)||According to scarring or nonscarring types|
- The diagnosis is often clear from the patient history and physical examination.
- Hair pull test: About 50 strands of hair are lightly tugged away from the scalp; if > 5 strands can be pulled out, the test is positive.
- Dermoscopy: examination of the scalp skin, follicle size and hair shaft diameter by magnification
- Microscopic examination of hair follicles and shaft: to determine the phase of hair growth (anagen, telogen) and structural abnormalities of the shaft
- Scalp biopsies from sites of active disease: to confirm diagnosis of cicatricial alopecia
- Trichograms: aids diagnosis and prognosis of nonscarring alopecia
- Definition: Androgenetic alopecia is a progressive, nonscarring alopecia; that affects the regions of the scalp with the most androgen-sensitive hair follicles; , resulting in a characteristic pattern of balding (bitemporal scalp in men and vertex and frontal scalp in women).
- Differential diagnosis
|Androgenetic alopecia in men (male pattern baldness)||Androgenetic alopecia in women (female pattern baldness)|
|Clinical features|| |
|Diagnosis|| || |
- The telogen (resting) phase of hair growth predominates → premature shedding of the resting hair follicles → diffuse, nonscarring hair loss
- Endocrine: hypothyroidism, hypopituitarism, hypoparathyroidism, diabetes mellitus.
- Drugs: anabolic steroids, antithyroid drugs, heparin, coumarin, antimetabolites (chemotherapy), oral contraceptives, etc.
- Nutritional: hypervitaminosis A, zinc deficiency, malnutrition states
- Stress: major surgery, sepsis, after childbirth (telogen gravidarum), acute or chronic illness (e.g., ), severe psychological stress
- Hair density reduces by < 50%
- Does not progress to complete baldness.
- Treatment: reassurance and manage underlying condition
- Definition: Hair loss in well demarcated patches due to immune mediated inflammation of hair follicles
- Prevalence: 1 in 1000 people
- Age: mostly in people < 30 years
- Sex: ♂ = ♀
- Clinical features
- Diagnostics: usually clinical, biopsy rarely necessary + histology, trichogram
- Differential diagnosis
- Prognosis: Is poor for alopecia universalis and totalis