The biological process of hair graying involves a reduction in the activity of the dermal papilla, where capillaries are located, and a decrease in melanocytes, the cells responsible for producing melanin and impacting hair color, according to recent observations from dermatologists.
Experts indicate that after the age of 40, hair follicles begin to exhibit signs of “fatigue,” accelerating the oxidation process. This intrinsic aging is compounded by what specialists term “environmental aging,” which encompasses the cumulative effects of hair treatments such as coloring, chemical processing, and excessive heat styling.
Hormonal fluctuations play a significant mediating role in hair health and are responsible for physiological changes throughout life. “During puberty, for example, there is an increase in testosterone; during pregnancy, an increase in female hormones. All of this impacts the hair,” explains Djane Camila Costa Morimoto, a trichologist and aesthetic biomedical scientist.
Changes occur in distinct phases. During puberty, increased sex hormones lead to heightened oil production, potentially affecting the scalp and causing dandruff, itching, and dermatitis. This period also marks the potential onset of genetic predisposition to baldness, with hair strands gradually becoming thinner.
Melanocytes, derived from neural crest cells, are located in the basal layer of the skin’s epidermis and play a crucial role in melanin production, which protects against UV radiation. These cells contain melanosomes, organelles that transfer pigment to nearby keratinocytes, determining skin and hair color. Individuals with darker skin tones have a greater number of melanosomes.
Dermal melanocytosis, a common type of birthmark previously referred to as “Mongolian spots,” appears as a flat, bluish-gray patch often found on the back or buttocks, though it can occur elsewhere on the body. These marks are typically present at birth and often fade during early childhood.
Dermal melanocytosis is more frequently observed in individuals of Asian and Japanese descent. Ultra-structural analysis reveals a characteristic extracellular sheath surrounding melanocytes in most cases of dermal melanocytosis. Treatment focuses on sun protection and cosmetic camouflage.
The condition is classified into two groups: classic presentations like blue nevi, Ota and Ito nevi, Mongolian spots, bluish macules of scleroderma, Hori’s nevus, and zygomatic fuscocaeruleus nevus, and a series of entities that resemble classic dermal melanocytosis histologically but require separate classification due to their clinical presentation and behavior.
