Hair Loss: Androgenic Alopecia

Summary

The video script explains the three-phase hair growth cycle: anagen, catagen, and telogen. Hair growth occurs in the anagen phase, with nutrients supplied by the dermal papilla. The catagen phase sees halted growth, and telogen is when the old hair is shed. Androgenetic alopecia shortens the anagen phase, leading to hair loss. Minoxidil, a treatment, may stimulate hair growth by increasing blood supply and follicle activity, potentially reversing hair loss. Visible results are expected after 2-4 months of treatment.

Takeaways

• 🌀 The hair growth cycle is a three-phase process occurring at the hair follicles.
• 🌱 During the anagen phase, hair matrix cells actively proliferate, producing new cells that form the hair shaft.
• 🔄 The catagen phase is a transitional stage where hair growth stops and the hair shaft keratinizes.
• 🍂 In the telogen phase, hair is shed as the follicle prepares for a new growth cycle.
• 🚿 Androgenetic alopecia is linked to higher levels of certain androgens, leading to shorter anagen and longer telogen phases.
• 📉 These hormonal changes result in progressively thinner and shallower hair follicles over time.
• 🌟 The typical pattern of hair loss due to androgenetic alopecia is observed at the vertex and frontotemporal regions.
• 💊 Minoxidil, a treatment for hair loss, may work by opening ATP-sensitive potassium channels and promoting hair growth.
• 🌡️ It might also increase vascular endothelial growth factor expression and enhance follicle vascularization.
• 🔁 The use of minoxidil can stimulate longer anagen phases, shorten telogen phases, and reactivate dormant follicles.
• ⏱️ It typically takes 2 to 4 months of minoxidil treatment to see noticeable improvements in hair growth.

Q & A

What is the three-phase cycle of hair growth?

The three-phase cycle of hair growth includes the anagen, catagen, and telogen phases. It takes place at the hair follicles where cells in the hair matrix are responsible for hair growth.

How do cells in the hair matrix receive nutrients during the anagen phase?

During the anagen phase, cells in the hair matrix receive nutrients from a capillary loop at the dermal papilla.

What happens during the anagen phase of hair growth?

During the anagen phase, the hair matrix actively proliferates, new cells are continually produced, and pushed upward to differentiate and form the hair shaft.

How long does the anagen phase typically last?

The anagen phase typically lasts for two to six years.

What occurs during the catagen phase of the hair growth cycle?

In the catagen phase, matrix cells cease activity, hair growth stops, and the base of the hair shaft keratinizes and migrates upward away from the papillary blood supply.

What is the telogen phase and what happens during this phase?

The telogen phase is the final stage of the hair growth cycle where hair transforms into club hairs, which then move up the hair sheath. At the start of a new anagen phase, the follicle re-grasps the papilla and a new hair grows.

How does androgenetic alopecia affect the hair growth cycle?

Androgenetic alopecia is associated with increased levels of certain androgens that lead to shorter anagen phases and longer telogen phases, resulting in progressively shallower follicles and thinner hair fibers.

What is the typical hair loss pattern seen in androgenetic alopecia?

The typical hair loss pattern in androgenetic alopecia is seen at the vertex and frontotemporal regions of the head.

How does minoxidil contribute to hair regrowth?

Minoxidil may act as an ATP-sensitive potassium channel opener and may elevate the expression of vascular endothelial growth factor, supporting follicle vascularization and potentially stimulating longer anagen phases and shortening telogen phases.

What is the initial response some patients may notice when using minoxidil?

Some patients may notice an initial increase in hair shedding due to an abbreviated telogen phase when they first start using minoxidil, which is temporary and indicative of a response to the treatment.

How long does it typically take to see visual improvement in hair growth with minoxidil?

It typically takes two to four months of treatment with minoxidil to reverse the process of androgenetic alopecia enough for patients to see visual improvement in their hair.