From terminal to Vellus, degrees of hair dysplasia

da terminale a vellus

Baldness, particularly androgenetic baldness, is a condition that has plagued humanity for centuries. As science and medicine have advanced, numerous treatments have been developed to combat this problem. In forums, medical conferences, and online communities, the effectiveness of these treatments is often the focus of discussions, bringing to light concepts such as the “Two Degrees of Dysplasia Rule.”

What does dysplasia mean?

The word “dysplasia” may sound technical, but its meaning is fundamental to understanding the nature of balding. It refers to the process in which terminal hair, which is thick, strong, and pigmented, becomes vellus hair, which is thin, light, and almost transparent. This transformation does not happen overnight, but is a gradual process that can be influenced by genetic, hormonal, and environmental factors.

The Classification of Dysplasia according to SITRI

The Italian Society of Trichology, a respected institution in the field of hair research, has provided a detailed classification of dysplasia. This classification, which dates back to publications in the 1990s, has been a milestone in the understanding of baldness. It includes several stages, from Anagen VII to Anagen vellus, each representing a different stage of hair miniaturization.

Description of Anagen Phases

The Anagen phases are fundamental to understanding the life and health of our hair. For example, Anagen phase VII, which lasts between 4 and 10 years, is common in women during periods such as youth and pregnancy. This phase represents optimal hair health, with rapid growth and a bulb deeply anchored in the scalp. In contrast, the Anagen vellus phase, typical of advanced balding, sees almost invisible hair with extremely slow growth.

  1. Anagen VII: This is the phase when the hair is at its peak in terms of health and growth. During Anagen VII, the hair actively grows for between 4 and 10 years. It is common in women, especially during youth and pregnancy, and in preadolescent children. At this stage, the hair has well-formed sheaths, optimal bulb depth, and rapid growth.
  2. Anagen VI: This stage lasts 2-4 years and is typical in men who show no signs of balding. The hair still has well-structured sheaths, adequate follicular depth, and normal growth.
  3. Pseudo-dysplastic anagen: During this phase, which lasts between 1 and 2 years, miniaturization of the hair begins. It is characteristic of androgenetic baldness in the upper head area. At this stage, the sheaths begin to show signs of weakening and hair growth becomes slower.
  4. Dysplastic anagen: This stage, which lasts between 6 months and 1 year, represents another stage of miniaturization. It is common in early androgenetic baldness. The sheaths are poorly formed and hair growth is even slower than in the pseudo-dysplastic stage.
  5. Anagen alopecic: During this phase, which lasts between 3 and 6 months, the hair is significantly miniaturized. It is associated with androgenetic baldness and, during this phase, sheaths are barely visible and hair growth is very slow.
  6. Anagen vellus or miniaturized: This is the final stage of miniaturization, typical of advanced balding. During Anagen vellus, which lasts between 1 and 3 months, the hair is almost invisible and its growth is extremely slow. These hairs are thin, light and almost transparent.

Dysplasia represents the process of miniaturization of the hair, which goes from a state of optimal health (Anagen VII) to a state of advanced baldness (Anagen vellus). This transformation is influenced by various factors, including genetics, hormones, and environment. Knowing and understanding these degrees of dysplasia is critical to effectively diagnosing and treating baldness.

Therapeutic Implications

When considering treatments for baldness, it is essential to keep in mind the degree of hair dysplasia. While it is possible to stop or slow miniaturization with appropriate therapies, it is rare for hair in advanced stages of dysplasia to return completely to its original state. This is why early diagnosis and intervention are critical.

The Two Degree Rule

This rule, often cited in medical circles, suggests that regardless of the potency or effectiveness of treatment, a miniaturized hair is unlikely to be “brought back” by more than two degrees of dysplasia. This concept underscores the importance of starting treatment as early as possible.

The Research Continues

Despite the challenges, experts and researchers are constantly searching for more effective treatments for baldness. The combination of drugs, therapies and procedures could be the key to effectively combating baldness in the future. With the advent of biotechnology and personalized medicine, there are hopes that we may see even more effective solutions in the future.

The Role of Genetics

Genetics plays a crucial role in baldness. While research has identified some genes associated with baldness, the full understanding of how these genes interact and influence hair growth is still in progress. Understanding the genetics of baldness could open the door to targeted and personalized therapies.

Future Treatments and Hopes

As research advances, new treatments and therapies emerge. From stem cell therapy to genetic modification, the possibilities are endless. While some of these treatments are still in the experimental stage, they represent hope for millions of people around the world.


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