Understanding Hair Loss

After bone marrow, hair is the second growing fastest tissue in your body, thus many metabolic derangements can be manifested with hair loss, and the condition maybe the first clinical sign of systemic disease in your body system.

Hair loss is the falling out of excessive hair that could result to unusual thinning or balding at specific spots in your body especially the head. The medical term for hair loss is known as “Alopecia”. The most common type of alopecia is that caused by our own genes, a condition known as “ANDROGENIC ALOPECIA” (commonly called male pattern hair loss or female pattern hair loss). This means that you can inherit the trait to loss hair from your parents. Hair loss in men and women can have significant psychosocial effects.

Genetic alopecia affects about 95% of all cases of balding or thinning hair in both men and women. It affects almost about 50% of all males and almost 40% of all females in the United States as they aged.

Another common type of hair loss is known as “Alopecia Areata” which is an autoimmune disease.

In men, hair loss follows progressive and stereotypical pattern.it usually begins with hair loss in the bi-temporal regions and then progresses to the vertex. However, in female, female pattern hair loss (FPHL) is a gradual onset, slowly progressive non-scarring alopecia, which can be seen any time after menarche, but it is mostly common in female age 20-40 years. FPHL results from progressive reduction of successive hair cycle time leading to miniaturization of hair follicles. These changes are mediated through interaction between androgens, their respective receptors and enzymes like 5-α-Reductase and cytochrome P-450 aromatase.

What are the Types of Pattern Hair losses?

• There are basically three types of pattern hair loss including:
• Diffuse central thinning (Ludwig type): This occurs when your hair loss is concentrated over frontoparietal region leading to thinning/rarefaction over central scalp but with intact frontal line.
• Frontal accentuation (Olsen type): This type of pattern hair loss results to widening of central parting line and therefore to Christmas-tree pattern.
• Frontotemporal recession/vertex loss.

What you should know about Hair-growth cycle?

• Hair growth is cyclic, with phases of growth (anagen), involution (catagen), and rest (telogen).
• The cycle of active growth (anagen phase) and rest phase are regulated by complex massage between the epithelium and the dermis although the mechanism is not well understood.
• In a normal scalp, most follicles grow (90 to 95% anagen phase), while a few are undergoing involution (maybe less than 1%), and the remainder are resting, I.e. 5-10% are in the telogen phase.
• At the end of the resting phase, your hair is released and shed and thus the next cycle is initiated.
• You should know that up to 100 hairs in telogen are shed from the head each day, and about the same number of follicles enter anagen.
• The duration of this anagen determines the length of your hair, and the volume of the hair bulb determines the diameter
• Follicles may become larger or smaller under systemic and localized influences that can alter the duration of anagen and the volume of the hair matrix.
• Androgens are important in regulating hair growth.
• At puberty, androgens increase the size of follicles in the beard, chest, and limbs and decrease the size of follicles in the bitemporal region, which can actually reshapes the hairline in men and women.

What are the Anatomy and Pathophysiology of hair loss?

• Male and female pattern hair loss (androgenic alopecia) is characterized by:
• Progressive visible thinning of scalp hair in genetically susceptible men and women.
• Androgenic alopecia is polygenic trait
• This trait is associated with variants region of the androgens receptor gene, located in the X chromosome.
• Hair thinning and subsequent thinning is due to gradual miniaturization of genetically marked hair follicles.
• This represent shortening of the anagen (growth) phase of the hair follicle with an increase in the telogen/anagen ratio of the affected scalp.
• This miniaturization results in the conversion of terminal hairs into smaller, barely visible, and depigmented vellus hair.
• Hair loss is androgen dependent as testosterone is the major circulating androgen that causes hair loss.
• This hormone is converted to dihydrotestosterone (DHT) by the enzyme 5-α-Reductase; DHT is the maximally effective chemical for hair loss.
• This means that balding scalp contains excess concentrations of 5-α-Reductase, DHT, and the DHT androgen receptors
• Therefore, young men and women with androgenetic alopecia have higher levels of 5-α-Reductase, more androgen receptors, and lower levels of cytochrome P-450 aromatase, which helps convert testosterone to estradiol, in hair follicles in the frontal region of the scalp than the occipital region.
• So the various clinical patterns of androgenic alopecia in men and women reflect the quantitative differences in the levels of 5-α-Reductase, the number of androgen receptors, and the levels of aromatase in specific regions of the scalp at various ages.

What could be the causes of my hair loss?

• Hair loss occurs when the cycle of your hair growth and shedding is by any means disrupted or when the hair follicles are destroyed and replaced with scar tissue; there are wide ranges of factors other than genetics that can result to hair loss, and many of these conditions are temporary and can be effectively treated by your dermatologist. These include:
• Autoimmune disorder: This is the common causes of hair loss known as alopecia areata. In this condition, the white blood cells attack the deepest parts of your hair follicle, commonly referred to as the bulb area, resulting in temporary hair loss. Another autoimmune disease that can result in hair loss is Lupus erythematous. This autoimmune disease affects the bulge of your hair follicle rather than the bulb and can cause permanent hair loss.
• Diseases:
• Fungal infections on the scalp such as ringworm (Tinea capitis), Kerion, and Favus can result in hair loss
• Bacterial infection on the scalp such as Folliculitis, Furuncles, and Carbuncles can cause thin hair.
• Skin cancers can also cause hair loss.
• Certain skin disease such as severe eczema, lichen planus (which affects the scalp) and Psoriasis can result in hair loss.
• Thyroid and endocrine gland disorders such as hypothyroidism and hypopituitarism can result in thin hair and brittle hair that breaks easily.
• Nutritional deficiencies: Iron deficiency anaemia, zinc deficiency, severe “crash” diets for weight loss and physiological disorders that can result in extreme nutritional imbalances such as anorexia and bulimia can result in hair loss.
• Poisons: Certain metals salts and heavy metals including arsenic, mercury, bismuth, lithium, thallium, cadmium and gold are poisonous, and can cause hair loss when you’re predisposed to them as a result of prolonged inhalation in industrial environment or by ingestion.
• Prescription drugs: Many categories of prescription drugs by physicians may present a risk of temporary hair loss as a possible side effect. E.g. chemotherapy drugs.
• Stress: Stress can cause a type of hair loss called telogen effluvium.
• Physical trauma to the scalp: Physical trauma to your scalp, such as wound from accident cutting, thermal burns from heat or fire, chemical burns from acids or other caustic substances, continuous pressure on the scalp from a tight fitting helmet, trauma injury from cosmetic surgery can all result to permanent hair loss.

Other factors that may interrupt the normal hair cycle, thus diffuse hair loss include:

Radiation exposure, hair loss following child birth, hair styling techniques, and hair styling products. Hair loss may last over both short and long time span.

What are the various clinical hair loss interventions available?

The clinical approaches to hair lost consist of finding the cause which requires a thorough history taking, and physical examination, laboratory investigation may be necessary. All these would enable appropriate treatments or counselling.

• History Taking: One of the most important steps in clinical interventions to hair loss is taking a detailed and complete clinical history. Your physicians would have to ask you to provide information of your illness like weight loss, surgeries and anaesthesia, any diseases (hormonal or thyroidal); nutrition, history related to hair loss that may run in your family. Your physician may also ask questions about the location(s) and duration of the hair loss.
• Physical Examination: After taking and documenting your personal health history, your physician would have to carry out a thorough physical assessment to ascertain the degree of the hair loss. The assessment could be:
• Checking the skin type of scalp, the scalp colour, distribution and presence of hair follicles, evidence of scaling would also be noted.
• Your hair density needs to be determined to ascertain if it’s normal or diminished.
• The “pull test” is then performed in order to assess the hair shedding level. NOTE: this test can show degree of the hair loss.
• Then a single hair strand is taken as sample for various microscopic analyses.