Post-inflammatory hyperpigmentation (PIH) is caused due to alterations in melanin pigment resulting from an inflammatory skin condition or any injury. Acne-induced PIH is commonly seen in females of the younger age group. 

Despite the presence of a wide range of therapeutic options, treatment of acne-induced PIH remains a challenge in Indian clinical settings due to reasons like relapse and a long course of disease; treatment-induced pigmentation; lack of clinical data on natural ingredients and lack of exclusive clinical practice guidelines for Indian patients. 

An experts’ panel discussion involving dermatologists all over India framed a consensus of expert opinions regarding acne-induced PIH utilizing topical depigmenting agents in Indian patients, which are as follows:

• Regarding epidemiology, PIH is highly prevalent in teenagers and young adults, particularly females in the age group of 15 to 30 years. People with colored skin types and grade II-III acne are more prone to PIH.
• Etiology of PIH is nutritional deficiency, skin disorders (acne, atopic dermatitis), metabolic disorders, certain medications, prolonged sun exposure, excessive use of cosmetics and home remedies, and pricking and scratching pimples.
• PIH have clinical features such as epidermal macules or papules of brown or black color.
• Pathogenesis includes inflammation and destruction of the basal epidermal layer which harms the production or regulation of melanin and causes hyperpigmentation.
• Diagnosis can be made by taking history to evaluate risk factors; utilizing clinical tests like dermoscopy examination and Wood’s lamp examination; evaluating polycystic ovarian syndrome (PCOS), thyroid disorders, vitamin D and B12 deficiencies and insulin, iron and hemoglobin levels by the lab investigations; and employing global acne grading scale (GAGS), Rosenberg’s self-esteem scale (RSES) and acne checklists/questionnaires.
• Medical treatment includes topical therapy with depigmenting agents like retinol, isotretinoin, glycolic acid, azelaic acid, kojic acid, nicotinamide, arbutin, niacinamide and a combination of vitamin C and E. These products should be non-sticky and the vehicle should be non-oily, preferably gel-based preparations and matt finish products. Anti-oxidants have been shown to reduce the occurrence of PIH when given along with other therapies. However, they may cause possible worsening of the condition due to melanin stimulation. Nicotinamide, kojic acid and arbutin are the preferred hyperpigmentation agents. Combination treatment with de-pigmentary molecules is superior to monotherapy. Azelaic acid doses must be increased gradually from 10% to 20% and it may start acting in approximately 2-weeks. A triple combination of retinoid, steroids and hydroquinone can be implied to be used twice a week.
• Nontopical therapy includes salicylic acid or retinol peel or a blend of salicylic acid and mandelic peels. Laser therapy can be employed independently or in combination with peels.
• For photoprotection, broad-spectrum physical and tinted sunscreens with SPF of 30 should be sed.
• For patient counseling, they should be explained the nature of the disease, kind of treatment, treatment-related outcomes, avoidance of pricking/popping the lesions and home remedies, regular sunscreen application, personal hygiene and balanced diet.
• Prevention measures include early initiation of acne therapy with isotretinoin and routine use of sunscreen along with a daily skincare regimen.

Source: Thomas J, Shankar K, Pujara S, et al. Consensus on management of acne-induced post-inflammatory hyperpigmentation: an Indian perspective. Int J Res Dermatol. 2021;7(2):336-45