Skin Problems - Pigmentation

Pheomelanin, a pigment responsible for lighter skin tones, has a yellow-red tint and offers limited UV protection, increasing susceptibility to sunburn. However, it helps regulate body temperature, reflecting heat away from the body in hot conditions. The MC1R gene controls melanin production, influencing skin and hair color, tanning, and melanoma risk. Melanin synthesis varies across individuals and racial groups due to genetics, sun exposure, and hormones like ACTH and MSH. Higher melatonin levels result in a grayish-brown skin tone.

Causes of Skin Pigmentation

Skin pigmentation is a common condition that can be triggered by various factors. The three leading causes of skin pigmentation are genetics, sun exposure, and particular medications. Understanding the fundamental causes of skin pigmentation will help us understand how to treat and prevent it.

Genetics

Skin tone is influenced by 125 genes and hormones, which control melanin production. Genetics play a significant role in determining skin color, predicting the number of melanocytes (skin cells that produce melanin). External factors, such as sun exposure, drugs, and cosmetics, can also alter skin tone over time. Melanin concentration varies among individuals, with darker skin tones typically having higher levels. Melanocytes produce melanin, which is transported and expanded during tanning and hyperpigmentation, and decreased during hypopigmentation.

Key points:

• 125 genes influence skin tone
• Genetics predict melanocyte count
• External factors alter skin tone
• Melanin concentration varies with skin tone
• Melanocytes produce melanin

Sun Exposure

Sun exposure triggers skin pigmentation as the body produces more melanin to defend against UV rays. Persistent UV exposure leads to pigmentation formation through the following phases:

UV radiation generates free radicals.

• Free radicals and UV light activate biological agents affecting melanocytes.
• Tyrosinase enzyme converts tyrosine into melanin pigments (red or brown).
• Biological substances enhance tyrosinase activity, increasing pigment production.
• Melanin is transferred from keratinocytes to skin cells, giving skin its color.
• Melanin is shed through natural exfoliation.

Key points:

• Sun exposure stimulates melanin production
• UV radiation activates melanocytes
• Tyrosinase enzyme converts tyrosine into melanin
• Melanin transfer gives skin its color
• Natural exfoliation sheds melanin over time.