Hair Loss

Why I Am Losing My Hair?

Hair loss or alopecia is a temporary or permanent loss of hair that mainly affects men but is also observed in women. Hear loss is associated with disorders that affect your scalp or the entire body such as illness, stress, iron deficiency, genetics, weight loss, aging, cancer treatment, and lifestyle.

What Is the Biology of Hair Growth?

Hair is made of a filament protein called keratin that is produced by the hair follicle found in the skin dermis and that contains specific stem cells. Hair follicles are dynamic structures that follow a cycle that leads to hair renewal.

This cycle follows a sequence of rapid growth (anagen), regression (catagen), and resting periods (telogen) of about 100 days. Following this sequence, older cells in the follicles are pushed upward to the surface of the skin and replaced by new cells [1]. Although without noticing a difference, we lose about 50-100 hairs per day.

What Causes Hair Loss?

1- Illness and Hair Loss

  • Telogen Effluvium: This condition is associated with an excessive resting period of the hair renewal process which is related to the telogen phase of the hair growth cycle. Telogen Effluvium is caused by many conditions such as surgery, stress, thyroid disorders, iron Deficiency, physical injury, change in diet and weight loss, and hormonal changes [2].
  • Autoimmune diseases (Alopecia Areata): In autoimmune diseases, our immune cells that should be targeting foreign invaders such as pathogens, start attacking hair follicles leading to hair loss [3].
  • Fungal infection (Tinea Capitis): Although it mainly affects children, this type of hair loss is caused by dermatophyte fungi that target the scalp leading to large inflammation, pustular plaques, and extensive hair loss [4].
  • Thyroid disorders (Hyperthyroidism and hypothyroidism): Both hyperthyroidism and hypothyroidism have been reported to increase the number of telogen hairs [5].
  • Sex hormone imbalance: This is also known as androgenic alopecia, where large hair follicles are induced to become smaller by the excessive secretion of the androgen steroid hormone, dihydrotestosterone [6].

2- Weight Loss and Hair Loss

A sudden weight loss associated with decreased protein intake and vitamin B3 deficiency has been associated with acute telogen effluvium. Additionally, associations between weight loss-related nutritional deficiencies, chronic telogen effluvium, androgenetic alopecia (AGA), female pattern hair loss (FPHL), and alopecia areata, have also been reported [7].

3- Stress and Hair Loss

Acute and chronic stress has been reported as an inducer of telogen effluvium. Several stress hormones, such as catecholamines, prolactin, ACTH (Adrenocorticotropic hormone), CRH (corticotropin-releasing hormone), b-endorphins, and glucocorticoids, and neuropeptides such as substance P have been shown to be directly or indirectly in affecting the function of hair follicles [8].

4- Iron Deficiency and Hair Loss

Iron is a cofactor for ribonucleotide reductase, a rate-limiting enzyme for DNA synthesis. As hair follicle cells are rapidly diving cells, their need for DNA synthesis increases, and therefore, iron deficiency can reduce the number of hair follicles produced [9].

5- Cancer Treatment and Hair Loss

Cancer cells are highly growing cells and to slow down or block their growth, chemotherapy is used as treatment. Chemotherapeutic compounds intercalate between the DNA of cancer cells which slow down their growth or trigger their cell death. However, as hair follicle cells are also highly growing cells, chemotherapy may also affect their growth [10].

6- Genetics and Hair Loss

An association between genetic variability of the androgen receptor (AR) a genetic predisposition for androgenic alopecia and male-pattern baldness has been reported. Analysis of the AR locus (gene position on the chromosome) on chromosome X (in both males and females), found that polyglycine-encoding GGN repeat is likely responsible [11].

What Are the Symptoms of Hair Loss?

Depending on the causes, hair loss can manifest in different ways:

  • Age-related gradual thinning on top of the head.
  • Circular or patchy bald spots on the scalp.
  • Stress- and emotional-induced sudden loosening of hair.
  • Full-body hair loss associated with chemotherapy.
  • Patches that spread over the scalp caused by fungal infections.

What is the Treatment for Hair Loss?

Most treatments for hair loss are associated with the determination of the underlying causes; however, some require changes in lifestyle, while others involve medications.

  • Reduce stress If the hair loss has stress-related origins.
  • If on the diet for weight loss, it is essential to choose a diet that have enough proteins, vitamins, and iron.
  • Hair loss should stop following the end of the chemotherapy.
  • In cases where the hair loss is permanent (e.g., surgery, physical injury), life would be much easier if you accept your appearance and live with it.
  • For genetic causes of hair loss such as androgenic alopecia and male-pattern baldness, a hair lotion containing minoxidil is used. Male-pattern baldness (men) is also treated with finasteride.
  • Other treatment for hair loss involves injection or skin application of steroids, artificial hair transplant, and hair transplant.


Although most hair loss is temporary, losing hair can be extremely stressful as it is part of who we are, and how we look. Most cases of hair loss can be treated, however, other therapeutic approaches exist and are being developed for permanent hair loss.


[1] Krause, K. and Foitzik, K., 2006, March. Biology of the hair follicle: the basics. In Seminars in cutaneous medicine and surgery (Vol. 25, No. 1, pp. 2-10).

[2] Malkud, S., 2015. Telogen effluvium: a review. Journal of clinical and diagnostic research: JCDR9(9), p.WE01.

[3] Alexis, A.F., Dudda-Subramanya, R. and Sinha, A.A., 2004. Alopecia areata: autoimmune basis of hair loss. European journal of dermatology14(6), pp.364-370.

[4] Hay, R.J., 2017. Tinea capitis: current status. Mycopathologia182(1), pp.87-93.

[5] Babb-Tarbox, M. and Bergfeld, W.F., 2008. Alopecia and Thyroid Disease. In Thyroid Disorders with Cutaneous Manifestations (pp. 121-143). Springer, London.

[6] Price, V.H., 2003, June. Androgenetic alopecia in women. In Journal of Investigative Dermatology Symposium Proceedings (Vol. 8, No. 1, pp. 24-27). Elsevier.

[7] Guo, E.L. and Katta, R., 2017. Diet and hair loss: effects of nutrient deficiency and supplement use. Dermatology practical & conceptual7(1), p.1.

[8] Hadshiew, I.M., Foitzik, K., Arck, P.C. and Paus, R., 2004. Burden of hair loss: stress and the underestimated psychosocial impact of telogen effluvium and androgenetic alopecia. Journal of investigative dermatology123(3), pp.455-457.

[9] Kantor, J., Kessler, L.J., Brooks, D.G. and Cotsarelis, G., 2003. Decreased serum ferritin is associated with alopecia in women. Journal of Investigative Dermatology121(5), pp.985-988.

[10] Botchkarev, V.A., 2003, June. Molecular mechanisms of chemotherapy-induced hair loss. In Journal of Investigative Dermatology Symposium Proceedings (Vol. 8, No. 1, pp. 72-75). Elsevier.[11] Hillmer, A.M., Hanneken, S., Ritzmann, S., Becker, T., Freudenberg, J., Brockschmidt, F.F., Flaquer, A., Freudenberg-Hua, Y., Abou Jamra, R., Metzen, C. and Heyn, U., 2005. Genetic variation in the human androgen receptor gene is the major determinant of common early-onset androgenetic alopecia. The American Journal of Human Genetics77(1), pp.140-148.

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