LENGTH, WIDTH AND GROWTH RATE
Length : range from <1mm to > 1 meter.
Average uncut scalp hair : 25 – 100 cm.
Width : from 0.005 to 0.06mm.
Growth rate: about 1 cm/ month (terminal hair).
1. Protects body surface from external injury.
2. Helps in sensory function.
3. Psycho – social importance.
4. Forensic importance:-
i. Identification of race, sex, age and religion.
ii. Cause of death can be determined.
iii. Time of death can be determined.
5. Assist thermo regulation mainly in lower animals.
ANAGEN (GROWING PHASE)
Lasts for about 1000 days.
Follicular cells grow, divide and become
Darkly pigmented portion is evident just above
the hair bulb.
CATAGEN (INVOLUTING PHASE)
Lasts for about 10 days.
Gradual thinning and decrease of the pigment.
Melanocytes stop producing melanin.
Matrix keratinocytes abruptly cease proliferating.
TELOGEN (RESTING PHASE)
Lasts for about 100 days.
Club-shaped proximal end shed from the follicle during
Growth of a new anagen hair leads to shedding of any
remaining telogen hair.
New hair does not “push out” the hair from the previous
EXOGEN (HAIR SHEDDING PHASE)
Recently added phase.
Describes relationship between hair shaft and base of
Hairs can be retained for more than one cycle.
Shedding phase is most likely independent of anagen and
Hair loss is a common reason for
male and female patients to
consult the dermatologist.
Natural shedding of hair accounts
for normal daily hair loss.
Recent measurements indicate
that the average rate of hair loss is
closer to 35 to 40 hairs per day.
MEDICAL CAUSES OF ALOPECIA
• Physical stress: surgery, illness, anemia, lack of sleep.
• Emotional stress: psychiatric illness, death of family member,
job loss, anxiety etc.
• Diet considerations: rapid weight loss or gain, unusual dieting
habits, protein intake failure, prolonged fasting.
• Hormonal causes: postpartum, oral contraceptives, menopause,
ingestion of testosterone containing hormone supplements.
• Endocrinopathy: hypothyroidism, hyperthyroidism.
Rapid and complete loss of hair in one
or most often several round or oval
Usually occur on the scalp, bearded
area, eyebrows, eye lashes and less
commonly on other hairy areas of the
Also known as Male pattern
baldness or Common baldness.
Reversible scalp hair loss that
generally spares parietal and
occipital areas of the scalp.
Usually occurs in twenties or early
Chiefly occurs in the vertex and
front temporal regions.
Temporary hair loss at the
conclusion of pregnancy.
Growth cycle generally returns to
normal within one year after the
baby is delivered.
Defined as a self-induced and recurrent
loss of hair. It includes the criterion of
an increasing sense of tension before
pulling the hair and gratification or
relief when pulling the hair.
Fluoxetine and other selective
serotonin reuptake inhibitors.
modification programs, may be
Dual treatment (behavioral therapy
and medication) may provide an
advantage in some cases.
Is a form of alopecia, or gradual hair
loss, caused primarily by pulling force
being applied to the hair.
also known as "Temporal alopecia”
form of hair loss.
hair loss that may be congenital but
usually appears in childhood as a
focal patch of loss that may be
complete or leaving fine vellus
inherited by the autosomal dominant
Observe in syphilis patient.
Hair loss can occur as patchy “moth-
eaten” thinning occurring in small
Alopecia cannot be cured totally.
Treatment is a very lengthy.
Researches are going on to invent a way to cure alopecia totally.
Some peoples implant false hair nowadays for their mental satisfaction.
• Walker SA, Rothman S. Alopecia areata: a statistical study
and consideration of endocrine influences. J Invest
Dermatol 1950; 14:403–13.
• Ikeda T. A new classification of alopecia areata.
Dermatologica 1965; 131: 421–45.
• Hamilton, J.B. (1951) Patterned loss of hair in man: types
and incidence. Annal NY Acad Sci 53, 708-728.
• Norwood, O.T. and Lehr, B. (2000) Female androgenetic
alopecia: a separate entity. Dermatol Surg 26, 679-682,
PubMed Label: 20345216.
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Explain every types of alopeica with their treatments.