What is hair loss? What is alopecia?
Hair loss (Alopecia) is a chronic dermatological disorder in which patients lose some or all of the hair on their scalp and in certain cases on their body as well.
Alopecia has few physically harmful effects, but it may lead to psychological consequences, including higher levels of reported anxiety and depression.
What are the types and causes of alopecia
Clinically, hair loss can be divided into 2 main categories, scarring and non-scarring alopecia.
Scarring alopecia is also known as cicatricial alopecia. It is very rare, only accounting 3 out of 100 cases of alopecia. The causes are varied, but include certain inflammatory conditions such as cellulitis and folliculitis. Usually causes irreversible destruction of hair follicles replaced by scar tissue, resulting in permanent hair loss.
Non scarring alopecia are more common and include male and female pattern hair loss (androgenetic alopecia), alopecia areata and telogen effluvium.
Alopecia areata is a type of non-scarring hair loss that can affect anyone regardless of gender or age. The hair loss initially occurs in round or oval patches. In a majority of cases, this hair loss grows back without any further hair loss.
Less often, the bald patches may grow larger and hair loss can affect the entire scalp or even worse, the entire body. In these forms of alopecia areata, the hair is less likely to grow back.
About 1 in 5 patients with alopecia areata report having a relative with alopecia areata. Although hair most often grows back on its own in alopecia areata, there are some treatments that may be beneficial.
Alopecia areata is considered to be an autoimmune disease in which the affected hair follicles are mistakenly attacked by a person’s own immune system.
Intralesional steroids are the first line of therapy in alopecia areata involving less than 50% of the scalp area. It is injected into and just beneath the dermis layer. Hair regrowth can be expected after 4-6 weeks.
Topical steroids are also commonly prescribed, although treatment has to be continued for at least 3 months to see results.
Telogen effluvium is a common, transient, reversible form of hair loss that can occur in response to certain medications, pregnancy, thyroid disease or some form of physical or psychological stress such as surgery or illness.
In the normal scalp, hairs are on varying cycles of resting (telogen) and growing (anagen) phases. When a person encounters the above stressors, it is likely that an appreciable number of hairs convert to the resting phase. Telogen Effluvium is characterised by pathologically increased shedding of normal telogen hairs more than 20%.
Telogen Effluvium becomes evident about 3-6 months after exposure to the triggering agent. Some medications that commonly cause telogen effluvium are anti-epileptic medications, hypertensive medications, and thyroid medications. Chemotherapy medications are also expected to cause hair loss.
Trichotillomania is also known as hair pulling disorder. It involves recurrent, self-induced irresistible urge to pull hair from the scalp, eyebrows, eyelids and other parts of the body. It is considered a mental disorder classified under Obsessive Compulsive and Related Disorders. Psychiatry treatment may be necessary to treat this condition if it persists beyond childhood.
Androgenetic alopecia is the most common type of hair loss and is so common that many experts consider it as just a normal variant. It is believed to be genetic, although the inheritance is complex involving either or even both parents.
Androgens are hormones including testosterone that are present in both genders. They have a major role in the development of pattern hair loss. Even though increased androgen activity leads to hair loss, most patients with pattern hair loss do not exhibit abnormal levels of testosterone.
For males, the pattern typically involves receding of the frontal hairline with or without hair loss at the vertex (or top of the scalp) and may or may not progress over time.
For females, the pattern is more variable, but most often spares the frontal hairline and involves diffuse thinning of hair over the crown of the scalp. This may or may not progress over time. It is important to note that this pattern of hair loss can be caused by an abnormal increase of androgens due to certain medical conditions such as polycystic ovarian disease or malignancy. These causes are usually associated with gynaecological symptoms such as abnormal menstruation.
How serious is my hair loss?
Androgenetic alopecia is not life threatening but requires constant treatment and monitoring, therefore an ideal classification with high amount of detail, practicality, and reproducibility is required to accurately diagnose and monitor this condition as well as to assess the outcome of treatment.
The adapted Norwood-Hamilton is a the most widely classification. The less severe “not bald” includes type I–III whereas the “bald” includes type IV–VII.
What are the treatments available for hair loss
Clinically proven treatments for androgenetic alopecia includes
- Topical minoxidil solution or foam
- Finasteride pills by mouth
- Hair transplant surgery.
Minoxidil has been used as treatment for alopecia since 1987. The mechanism of action is not exactly known, but it has been shown to shorten telogen phase, lengthen anagen phase, and is a hair growth stimulator.
Proposed mechanisms of action include increased circulation through vasodilatation and angiogenesis, opening of potassium channels, anti-androgenic effect, release of growth factors, stimulation of dermal papilla, and immunosuppression.
Topical Minoxidil should be applied twice daily for best results. It is recommended for alopecia of less than 5 years duration, where the hair follicles are not yet deeply miniaturised.
Finasteride is a synthetic analogue of steroid hormones like testosterone and DHT. It is a selective and competitive inhibitor of the 5-alpha-reductase enzyme types II and III, responsible for the conversion of testosterone into dihydrotestosterone.
Finasteride has been shown to increase the ratio of anagen to telogen hairs. It is shown to be effective in increasing hair weight rather than hair count.
Approximately 2% of men on Finasteride report adverse sexual effects such as decreased libido, erectile dysfunction and ejaculation disorder. These side effects improve over 2-4 years, after which it returns to normal.
Hair transplant remains the only viable treatment for more advanced hair loss, but the procedure requires donor occipital hairs. Hair transplantation involves harvesting of hair from the occipital area followed by reimplantation into the bald vertex and frontal areas. With modern techniques, graft survival in excess of 90% can be achieved.