Hair loss and diabetes

Dr Louise Johnson explains the connection of hair loss in people living with diabetes.

The average human normally sheds 50 to 100 hairs per day according to The American Academy of Dermatology. Losing hair is part of the hair lifecycle. As one hair is shed, another replaces it. The hair follicle is a complex mini organ that produces hair from terminal differentiated cells called keratinocytes. On average, a human has between 2 and 5 million hair follicles of which 100 000 are on the scalp. But there is a difference between shedding hair and hair loss.

The hair follicle

The growth of the hair follicle can be divided into three phases:

1. Anagen (growth)

Anagen growth is the active phase in which the hair follicle takes on its onion shape and works to produce the hair fibre. This phase lasts between two and six years. During this phase, rapid cell division occurs in the hair bulb. In addition, new hairs begin to protrude from the scalp.

2. Catagen (transition)

Catagen is a transitional phase that last two to four weeks.

3. Telogen (rest)

This phase last three to five months and is the resting phase.

Hair loss

Excessive hair shedding can occur during times of stress or after pregnancy. This is not the same as hair loss which is referred to as alopecia, occurs when something stops the hair from growing. This falls into three categories:

1. Androgenetic alopecia
2. Alopecia areata
3. Telogen effluvium

Androgenetic alopecia

This is characterised by male pattern baldness and can happen to both males and females due to hormonal changes. The incidence varies across races, but its prevalence increases with age, visibly affecting 57% of women and 73.5% of men who are at least 80 years old.²

Alopecia areata

This develops when the immune system attacks the hair follicle and can be associated to Type 1 diabetes since it’s an autoimmune disease.

Telogen effluvium

This is due to a response to stress.

Is hair loss a symptom of diabetes?

Hair loss can occur in both Type 1 and Type 2 diabetes. In Type 1 diabetes there are often other autoimmune diseases associated. Alopecia areata is one where antibodies attack the hair follicle which leads to hair loss. Hashimoto thyroiditis is another autoimmune disease which causes dry skin and hair loss due to an underactive thyroid gland.

In Type 2 diabetes, cortisol levels (stress hormone) can be high due to insulin resistance. Excess cortisol can disrupt the hair follicle leading to hair loss.

In a 2019 study¹, it was shown that in Type 2 diabetes of African origin were associated with increased risk of central scalp hair loss. There may be a genetic factor to central hair loss.

Clinicians should also screen women with central scalp hair loss for Type 2 diabetes if they are not yet diagnosed. Whether successful treatment of Type 2 diabetes might protect African women from central scalp hair loss remains to be determined.

In long-standing diabetes, both Type 1 and Type 2, there is often microvascular (small vessel) damage which leads to impaired blood flow to the affected area as well as less nutrients and oxygen. This can be seen in eye, kidney, feet and hair. Typically seen in patients with peripheral neuropathy (lower leg loss of sensation due to nerve damage), the hair growth on the lower leg is reduced or absent.

Medication can also contribute to it. In patients taking metformin it’s important to monitor the vitamin B12 and folate levels. This can be diminished which would cause impaired hair growth.

Management of hair loss in diabetes

1. Good glucose control is important. Make sure that your average blood glucose (HbA1c) is below 7% or the target that your healthcare practitioner suggests.
2. Healthy eating, exercise and stay hydrated.
3. Make sure your thyroid levels, vitamin B12 and folic acid levels are normal. Also remember to check iron levels since iron carry red cells and oxygen. If not replace as needed.
4. Get enough sleep.
5. Be gentle when washing and brushing your hair.
6. Seek medical help early.
7. In cases where it interferes with quality of life, a wig or hair prosthesis should be considered until the hair grows back.

References

1. Coogan P.F. Traci n et. al. “Association of type 2 diabetes with central scalp hair loss in a large cohort of African American women” Int. Jour of women’s dermatology, 5(2019) p 261 – 266
2. Gan DCC, Sinclair RD “Prevalence of male and female pattern hair loss in Maryborough.” J Investig Dermatol Symp Proc. 2005;10(3)184-9

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