Postinflammatory hyperpigmentation (PIH) is a common sequela of inflammatory dermatoses or injury to the skin. It occurs most commonly in darker skin types. Depending on the etiology of the hyperpigmentation, pigment may be deposited in the dermis or epidermis with important implications for treating the pigment changes. It is a common sequela of laser treatment, particularly in darker skin phototypes (Fig. 27.1).
PIH seen after a series of treatments with nonablative fractional resurfacing for a scar. The PIH resolved on its own within 3 weeks
Incidence: common, especially in darker skin types
Race: more common in darker skin types
Precipitating factors: any inflammatory disorder or injury to the skin can produce hyperpigmentation. It may also result from laser therapy, dermabrasion, cryotherapy, or chemical peels. It presents more exuberantly and with a greater duration in darker skin phototypes
Basal cell layer pigmentation and dermal melanophages are seen.
In epidermal PIH, patients display indistinct tan to dark brown macules at sites of previous skin inflammation. In dermal PIH, there is more of a brown-gray hue.
Mastocytosis, macular amyloidosis, minocin hyperpigmentation, exogenous ochronosis, melasma, and erythema dyschromicum perstans.
PIH does not worsen in the absence of further insult or inflammation at the affected site. PIH usually resolves over a period of a few months. In the case of dermal hyperpigmentation, there may not be improvement.
KEY CONSULTATIVE QUESTIONS
Sun exposure, sunscreen use
Time of onset
Recent rashes, injury, or treatment of skin
While there is no medical indication to treat PIH, many patients are as bothered by PIH as they are by the processes that produced it initially. Furthermore, PIH can endure far longer than the original eruption. There are multiple treatments including topical, laser, and chemical peels (Table 27.1). It is essential to first determine the cause of the hyperpigmentation. Culprits range from hemosiderin to pigment to vascular. Without determining the etiology correctly, treatment will, at best, provide no improvement, or worsen the PIH. Frequently, the safest and most effective treatment is time. Attempted treatment of PIH, especially in darker skin phototypes, can often worsen and prolong hyperpigmentation. Normally, epidermal PIH will resolve on its own over a period of months.
TABLE 27.1Post-inflammatory Hyperpigmentation treatment