Many people are affected by brown spots on the skin. There are various causes of brown spots and they tend to be accumulative. Better understanding the different causes of hyperpigmentation allows you to take preventive and curative measures, depending on your skin type and the type of mark.
Summary
Hyperpigmentation and brown spots appear because of increased melanocyte activity, which are melanin-producing epidermal cells. Melanin is the biological pigment that gives skin its light or dark color. Melanin is also what gives our hair and eyes their color.
Any internal or external factor that stimulates melanocyte activity in a person can be considered a cause of hyperpigmentation.
Sun exposure is one of the main causes of hyperpigmentation. Brown spots caused by the sun can appear on all exposed areas of the body, e.g. the face, neck, décolleté, hands, forearms, shoulders and back.
When combined with other causes of skin pigmentation, the sun increases the likelihood of brown spots appearing on all areas of the body.
With age, the skin becomes thinner, more fragile and more sensitive to both internal (hormones, etc.) and external (sun, pollution, etc.) agents, resulting in brown spots associated with other signs of aging such as wrinkles and loss of firmness.
Formation of brown spots is associated with both the sun and skin aging. It is called photo-aging, i.e. premature skin aging caused by repeated exposure to UV rays. The sun is one of the main causes of age spots.
Hormones, and more specifically female sex hormones, are one of the main causes of hyperpigmentation. We call hormone-related hyperpigmentation “chloasma”.
There are a variety of circumstances under which hormonal brown spots appear, and they all involve excess hormones: pregnancy, hormonal contraceptives, hormone replacement therapy. Pregnancy is a period during which there is a particular risk of brown spots called melasma, or pregnancy mask.
Hormonal brown spots appear on the face: forehead, cheeks, nostrils, upper lip, chin. When hormone levels return to normal, for example after childbirth or on discontinuing hormone therapy, the marks may eventually fade, but they sometimes remain and require appropriate treatment.
Post-inflammatory hyperpigmentation is one of the most important causes of hyperpigmentation, particularly in people with black or mixed skin. Following skin inflammation (acne, eczema, psoriasis, a chemical peel or laser treatment, etc.) or any other lesion (burn, abrasion, etc.), the skin repairs itself but at the same time produces a greater amount of melanin, which is why brown spots, or a hyperpigmented scar, can appear at the site of the lesion.
Some medicines are known to be causes of hyperpigmentation. They give the skin an abnormal color. Examples include amiodarone, hydroxychloroquine and phenothiazine neuroleptics.
These are not to be confused with photosensitizing molecules, which can cause an inflammatory reaction under the effect of the sun leading to redness, plaques, itching, etc. Examples include non-steroidal anti-inflammatory drugs and fluoroquinolone antibiotics.
Some medicines are both photosensitizing and cause hyperpigmentation.
Ask your doctor or pharmacist to find out if your treatment includes any medicines known to cause hyperpigmentation.
If so, it is highly recommended to wear sun protection throughout the treatment. On discontinuing treatment, pigmentation returns to normal, but this can sometimes take months, or even years.
Pollution makes skin drier, duller and more sensitive (even intolerant). It promotes premature skin aging. Oxidation of the molecules present in the skin, in particular sebum, contributes to the formation of brown spots. Pollution is therefore one of the causes of hyperpigmentation.
Causes of hyperpigmentation include environmental factors, such as smoking, whether active or passive.
Excess blue light is also thought to be involved in premature skin aging and to cause brown spots. Blue light is a part of the visible light spectrum. It’s produced naturally by the sun, and artificially by LED lighting and screens. Spending many hours each day in front of screens can therefore have harmful consequences on the skin, although not comparable to sun exposure.
The skin condition called acanthosis nigricans is characterised by the presence of thick, dark plaques in some skin folds. It can be associated with certain metabolic diseases, for example diabetes or polycystic ovary syndrome.
Lupus is an autoimmune disease in which skin can become very red, particularly on the face. These red patches can then turn brown and remain over time. The main treatment for lupus, hydroxychloroquine, is another cause of hyperpigmentation.
Some vitamin deficiencies are thought to contribute to the formation of brown spots, and to therefore be additional causes of hyperpigmentation... Vitamin B12 is an example. It helps regulate melanin in the skin. If there is no vitamin B12, the skin produces more melanin and hyperpigmentation spots appear. To avoid this, you need to eat foods containing vitamin B12: meat, fish, dairy products. Vegetarians and vegans should generally consider vitamin B12 supplementation to avoid developing deficiencies.
The causes of hyperpigmentation are extremely varied: hormones, medicines, deficiencies, etc. By acting on these different causes of hyperpigmentation, you can limit the appearance of brown spots. A special mention for the sun, which stimulates all causes of hyperpigmentation and increases the likelihood of developing brown spots.
