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Alopecia
In order to fully understand the factors surrounding anagen and telogen effluvium it is necessary to know the stages of hair growth in hair cycle
Hair Growth Cycle
Scalp hair-follicles have a four phase cycle. Anagen (growth), Catagen (transition), Telogen (resting) and Exogen (hair-shaft evacuation).
The Anagen Phase - During the process of folliculo-regenesis, the follicle + epithelial sheath + new hair shaft is recreated. During its growth (anagen) phase the hair shaft continues to gain length for a period of 2-7 years. Approximately 80-85% of hair follicles are in anagen. Hair growth rates range from 0.5cm - 1.45cm per month.
The Catagen Phase - mitosis ceases, the follicle enters a period of degeneration. Catagen accounts for approximately 3% of hair follicles. The Epithelial sheath shrinks forming a minute "club root" at the proximal end of the hairshaft. Catagen lasts for approximately 10-20 days.
The Telogen Phase - approximately 12-20% of hairshafts are in the amitotic (resting) phase. Eventually (up to 3 months ) the hairshaft vacates the follicle.
The Exogen Phase - in which the hair-shaft is evacuated.
ANAGEN / TELOGEN Effluvium
Excessive shedding of scalp hair
Anagen Effluvium - hairloss during anagen - the onset may be rapid (within 2-4 weeks of the cause). Hairloss may be severe. Causes include:- Chemotherapy drugs (antimitotic agents), Radiotherapy, Malnutrition, Seborrhoeic dermatitis, Oral contraceptives, Vitamin A poisoning, Iron deficiency, Chronic infections and some drugs.
Telogen Effluvium - relating to a specific form of diffuse alopecia - eviction of hairshafts that have prematurely entered the telogen phase. Excessive loss of hair can occur. Telogen Effluvium tends to become apparent 6-12 weeks following the cause. Such a hairloss can result in 1-2cm stubble in extreme cases within weeks. Causes include: Pyrexia (body temperature reaching 103.5 C +), Childbirth (rare), severe infection (especially toxaemia), major surgery, protein deficiency due to unsupervised crash diets, drugs including beta blockers, anti-depressants, severe psychological stress.
Professional advice should be sought in all cases of hairloss. Self diagnosis is not advised. We offer treatment for these conditions. For further advice please contact our helpline.
Helplines
London - 0207 40 40 072
Gidea Park - 01708 728 980
Benfleet - 01268 795 495
or e-mail
The Holborn Hair & Scalp Clinic
Specialists in hair loss and scalp conditions
Tel: 0207 404 0072
