Skin ranges in shade from dark brown to pale pink. But what gives our skin its color? And what are some of the common diseases and conditions associated with skin pigmentation?
Skin pigmentation: The basics
The pigment in our skin is formed by a substance called melanin. Melanin is a complex polymer derived from the amino acid tyrosine. Melanocyte cells are specialized cells that are distributed throughout the top layer of our skin (the epidermis). Once melanin is produced, it spreads to other skin cells nearby, giving a uniform appearance of color in our skin. Sometimes melanocyte cells can cluster in groups or “nests”, forming moles, freckles, age spots and other skin marks.
In most people, melanin is something we take for granted, but, in some instances, there can be too much, too little or no melanin present at all in our skin.
is a condition that occurs when there’s too much melanin present in the skin. This usually harmless condition is a result of melanocyte cells that form in highly concentrated groups within the skin. It can also be caused when the sun over stimulates the production of melanin in the skin. Hyper pigmentation can affect any race, although it is more common in people of Asian, Mediterranean or African descent. It can also occur on any area of the body.
There are a few common types of hyper pigmentation:
However, there are lentigines that occur without sun exposure.
Not to be confused with freckles, lentigines are more widely distributed, are generally darker in color and do not go away or fade during winter months as freckles do. Lentigines normally pose no risk, but they can sometimes be confused with melanomas, so it’s good to have them looked at by a doctor if you are suspicious.
Another form of hyper pigmentation is melasma. Melasma, sometimes also called chloasma, is a condition where tan or brown patches appear on the body, typically on the face. They can often be triggered by hormonal changes, and frequently occur in pregnant women for this reason. Sometimes people even refer to melasma as “the mask of pregnancy”. Melasma can also be caused by contraceptives, hormone replacement therapy and excessive sun exposure.
While it’s more common in women, men can still suffer from melasma. The increased amount of melanin in the skin that causes this condition can occur in the epidermis (top layer of skin), dermis (middle layer of skin) or a combination of both. Melasma is not a dangerous condition, but it is one that can undoubtedly detract from quality of life. Luckily there are treatments available, the most common of which is using a brightening cream with the ingredient hydroquinone.
On the other end of the spectrum, skin can also lose pigmentation. This is a process known as hypo pigmentation, sometimes called depigmentation, and occurs when melanocyte cells reduce their production of melanin. Hypo pigmentation is often caused by trauma, including burns, blisters, scrapes or other injuries that can scar and deplete the melanin in the skin.
Hypo pigmentation can also be caused by a congenital condition a person is born with, such as vitiligo or albinism, or an improperly conducted skin treatment such as a chemical or laser peel. In some cases, hypo pigmentation can be the result of an inflammatory skin reaction or skin infection that damages the melanin production in the skin. Seborrheic dermatitis, tinea versicolor, pityriasis alba and eczema are examples of this. Hypo pigmentation is usually a harmless condition but it is difficult to treat; however, some treatments do exist that can minimize the appearance of hypo pigmentation. These treatments include specialized creams, topical treatments, laser treatments or some prescription medications recommended by a doctor or dermatologist.
Vitiligo and Albinism are two of the most common and widely known forms of hypo pigmentation.
Vitiligois generally harmless and it is not contagious, but its cosmetic appearance can cause emotional and psychological distress in people who suffer from it. There are several treatments that can help reduce the appearance of vitiligo, including corticosteroid creams, depigmentation treatments and UVA and UVB phototherapy. Some of these treatments come with their own side effects, so it’s recommended to discuss options with a doctor.
There are different types of albinism with varying degrees of severity, resulting in a range of skin, hair and eye pigments. Skin can be completely white, reddish brown, or even normally colored. Hair and eye color also vary widely depending on the type of albinism and degree of severity. Some rarer forms can cause life-threatening immune or neurological problems. Albinism is caused by a defect in one or several of the genes responsible for the production of melanin.
No matter the kind of albinism, all people with the disease suffer from vision problems, including light sensitivities, misalignment issues, poor vision and more. Albinism is an incurable condition that generally does not worsen over time. People with albinism are at an increased risk for skin cancer and should apply protection and be very careful in the sun.
Negative social and emotional components of the disease are also common. While treatment is limited, genetic counselling, proper eye care and vigilant monitoring of the skin for signs of skin cancer are recommended.