Hair is one of the skin appendage. Though it appears as dead structure, it is undergoing continuous cycles of growth and loss. As compared to animals, human beings are less hairy due to process of evolution. The hair growth pattern is very important part of overall appearance of individual.
Hair growth pattern varies individually and according to gender. The pattern of hair growth is determined in when we are in womb. Subsequently, with advancing age and changing hormonal pattern, hair density changes.
Every hair has cyclical growth. It has growth phase (Anagen), resting phase (Telogen) and involution phase (Catagen). The duration of these stages varies according to body site.
Factors which control hair growth
• Nutrition – iron, minerals, vitamins
• Hormones - androgens, thyroid
• Physical damage to hair – withering of hair shaft due to dryness, heat application
• General health
• Drug intake (medicines)
Also called as alopecia. It is broadly divided as diffuse and localized, scarring and non-scarring and patterned hair loss.
Diffuse hair loss
Hair loss is from all over scalp. Normally up-to 100 hairs are lost daily which re-grow. If more than 100 hairs are lost daily from scalp then it is considered as significant.
Common causes are
• After acute febrile illness
• Chronic illness
• Nutritional deficiency – iron, minerals, vitamins
• Thyroid diseases
• Drug intake like post chemotherapy
• Scalp diseases like dandruff
Diffuse hair loss is usually reversible and treatable.
Patchy or localized hair loss
Alopecia areata – it is a patchy loss of hair noticed suddenly. Usually self limiting and hair re-grow with treatment.
Trichotillomania – emotionally disturbed patients pluck their hair either knowingly or unknowingly. Psychiatrist intervention needed.
Scalp diseases or trauma which lead to scar formation and hair loss locally. Hair loss is permanent and hair cannot re-grow unless transplanted.
Patterned hair loss
It is due to effect of androgens on scalp hair. Androgens cause miniaturization of scalp hair in a pattern. It is seen in males and females as well.
Males – Hair line start receding from late 20s and early 30s in a pattern (Frontolaterally and over crown of scalp). The severity of hair loss depends on genetic susceptibility. If early treatment is started, progression can be arrested in majority. Treatment has to be continued lifelong and is safe.
Delayed treatment cannot restore lost hair. They are candidates for hair transplantation.
Females - Thinning of hair density over crown area start developing in late 40s. Can be seen in young girls if associated with androgen excess (obesity, polycystic ovary disease). Progression of late age onset can be stopped with treatment which has to be continued lifelong. Young girls canbe treated with hormonal therapy, weight reduction.
Myths about hair care
• Regular oil application to scalp helps to grow longer hair and prevent hair graying – Hair oils act like hair conditioners. It does not affect hair growth. Scalp massage during application may increase scalp circulation which gives relaxation effect.
• Shampoos cause hair loss - Loose hair are shed off during scalp wash which otherwise also would have shed gradually. Since they are shed off together, it gives impression of hair loss. Shampoos do not affect hair growth. Excessive use may cause hair shaft withering and increased breakability.
Male and female patients with advanced hair loss cannot be restored natural looking hair line with medicines. Such patients are candidates for hair restoration surgery.
Technique of hair transplantation
Back (Poserior) portion of scalp hair are usually seen retained in advanced male pattern hair loss. Because these (occipital) hairs are resistant to androgen effect. Hair follicles (individual hair unit) are harvested from this area and grafted to frontal bald areas. The restored hair line is permanent and natural looking compared to wigs or hair patch. The results of surgery depend upon severity of balding and surgeon’s expertise.
Two techniques for hair transplant
• Follicular unit transplant – Strip of hair is removed from occipital scalp. Individual hair units are separated by careful dissection and transplanted. This technique is useful for treatment of large bald areas, quicker and less expensive.
• Follicular unit extraction – Individual hair units are extracted from occipital scalp and transplanted. It is time consuming, expensive technique but without scar on occipital area.
Technique selection depends on patient’s scalp condition, severity of hair loss and surgeon’s familiarity with the technique. Repeat sessions of surgery may require for larger bald areas.
No hospitalization is required. Patient can return home same evening.
Hair transplantation can be used in restoration of eyebrows, eyelashes or scarring alopecia.
Dr Santosh D
MD (Skin & VD), DDV, Fellowship in hair transplant surgery (South Korea), Fellowship in STDs and AIDS (Thailand)
Consultant Dermatologist, Cosmetologist & Hair Transplant Surgeon, Thane