However, untreated PIH can last for months, years, or even be permanent if deeper layers of skin are affected. Even minimal skin exposure to the suns ultraviolet rays can sustain hyperpigmentation. Daily use of SPF 15 or higher sunscreen can minimize such a risk. Causes
Risk factors for the development of acne, other than genetics, have not been conclusively identified. Possible secondary contributors include hormones, infections, diet, and stress. Studies investigating the impact of smoking on the incidence and severity of acne have been inconclusive. Sunlight and cleanliness are not associated with acne. Genes
Acne appears to be highly heritable; genetics explain 81% of the variation in the population. Studies performed in affected twins and first-degree relatives further demonstrate the strongly inherited nature of acne. Acne susceptibility is likely due to the influence of multiple genes, as the disease does not follow a classic (Mendelian) inheritance pattern. These gene candidates include certain variations in tumor necrosis factor-alpha (TNF-alpha), IL-1 alpha, and CYP1A1 genes, among others. The 308 G/A single nucleotide polymorphism variation in the gene for TNF is associated with an increased risk for acne. Acne can be a feature of rare genetic disorders such as Aperts syndrome. Severe acne may be associated with XYY syndrome. Hormones
Hormonal activity, such as occurs during menstrual cycles and puberty, may contribute to the formation of acne. During puberty, an increase in sex hormones called androgens causes the skin follicle glands to grow larger and make more oily sebum.
Therefore, it is useful in treating individuals with acne who are also affected by post-inflammatory hyperpigmentation. Azelaic acid may cause skin irritation. It is less effective and more expensive than retinoids. Azelaic acid also led to worse treatment response when compared to benzoyl peroxide. When compared to tretinoin, azelaic acid makes little or no treatment response. Salicylic acid
Salicylic acid is a topically applied beta-hydroxy acid that stops bacteria from reproducing and has keratolytic properties. It is less effective than retinoid therapy. Salicylic acid opens obstructed skin pores and promotes the shedding of epithelial skin cells. Dry skin is the most commonly seen side effect with topical application, though darkening of the skin can occur in individuals with darker skin types. Other medications
Topical and oral preparations of nicotinamide (the amide form of vitamin B3) are alternative medical treatments. Nicotinamide reportedly improves acne due to its anti-inflammatory properties, its ability to suppress sebum production, and its wound healing properties. Topical and oral preparations of zinc are suggested treatments for acne; evidence to support their use for this purpose is limited. Zincs capacities to reduce inflammation and sebum production as well as inhibit C. acnes growth are its proposed mechanisms for improving acne. Antihistamines may improve symptoms among those already taking isotretinoin due to their anti-inflammatory properties and their ability to suppress sebum production.Hydroquinone lightens the skin when applied topically by inhibiting tyrosinase, the enzyme responsible for converting the amino acid tyrosine to the skin pigment melanin, and is used to treat acne-associated post-inflammatory hyperpigmentation.