Skin Pigmentation & Acne
Acne can cause brown or dark brown pigmented spots on the skin and these are the most common skin complaint seen by dermatologists. These dark spots are usually caused by inflammatory acne and are more frequently seen in people with dark skin. The dark spots should not be confused with the red marks caused by acne, which are temporary and show healing.
Hormones can cause dark spots or make them worse. When hormones are increased, such as during pregnancy, the dark pigment marks caused by acne may last longer and also be darker.
What causes the red spots?
Red or purple marks are usually seen at the site of acne in people with light skin. These marks usually last around 8 to 10 weeks and occur as a result of the natural healing process and repairing of the skin.
What is post inflammatory hyperpigmentation?
Post inflammatory hyperpigmentation (PIH) is the discolouration of skin following a wound such as acne that is associated with inflammation. It is more common in people with darker skin. The exact colour of the PIH will depend on the skin tone and how discoloured it is. When the skin is inflamed by acne it makes it produce more melanin. Since melanin gives the skin its colour, this extra melanin will make the skin becomes darker and discoloured. This remains even after the skin has healed. Usually, the more inflamed the skin is the more severe the PIH. PIH also appears darker and larger if you pick at the acne or ‘pop’ your spots. Whilst PIH is not permanent, it can last for a very long time.
What can be used to treat acne?
There are treatments available both for the treatment of acne and for the treatment of PIH.
- Benzoyl peroxide is a cream that is applied directly to the skin and is effective in treating the inflammation caused by acne. It works by producing oxygen in the skin. This helps to kill the bacteria that causes acne and therefore helps heal the skin. This treatment should be continued even after the skin has cleared up as it helps to prevent the return of acne. The most common side effects of this treatment are dryness and flaking.
- Retinoids can also be applied directly to the skin and treats acne by increasing the rate at which new skin cells are made. As well as treating the inflammation, retinoids also treat the dark spots caused by acne as they are able to bleach the skin. Applying retinoids directly to the skin may cause extreme dryness, redness or irritation, which could lead to the dark spots worsening.
- Antibiotics such as tetracycline should be used when acne first appears as they prevent inflammation and therefore the dark spots left by acne. It is the most commonly prescribed antibiotic for treating acne. Tetracycline works by decreasing the amount of bacteria on the skin that cause acne. This drug should be taken one hour before or two hours after meals as food can reduce its effectiveness. It should not be taken in during pregnancy or by children under the age of 12 years because it can cause tooth discolouration. Side effects seen can include vaginal thrush infections in women and a decrease in the effectiveness of oral contraceptives. You should therefore use other contraceptive methods while taking this medicine.
- Cosmetic preparations containing hydroquinone are available over the counter. However these preparations are not recommended because there is concern that hydroquinone is a cancer causing chemical. It works by preventing melanin production which therefore makes the skin lighten. When used for PIH, you should be careful to apply hydroquinone only to the affected area to avoid lightening the rest of your skin.
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