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Periorbital hyperpigmentation (POH) is a common dermatologic condition with an enigmatous pathogenesis that can have a significant psychological impact on the patients’ quality of life. Although easily diagnosed, cure is not easy. POH is known by various synonyms including periorbital melanosis, periocular hyperpigmentation, infraorbital darkening, dark circles, infraorbital hyperpigmentation, or idiopathic cutaneous hyperchromia of orbital region. Factors promoting its occurrence can be exogenous as well as endogenous. Chiefly, the diagnosis is based on clinical examination. Finding the relative cause of POH is the most important factor in its management. Worldwide data regarding the prevalence and incidence of POH is less, because this disease lacks a reasonable etiologic explanation. An Indian study has shown that the prevalence of POH is 30.76% and is most prevalent in the females of age group 16–25 years.
POH has multifactorial etiology. Various proposed etiologic factors include constitutional pigmentation, thin and translucent eyelid skin leading to vascular prominence, shadowing effect due to lax skin and ageing, periorbital edema, dermal melanocytosis, postinflammatory hyperpigmentation, extension of pigmentary demarcation lines, ocular hypotensive drugs, periorbital melasma, periorbital lichen planus pigmentation, periorbital acanthosis nigricans, and environmental causes such as ultraviolet (UV) radiation, atopy, lack of sleep, stress, alcohol, and smoking.
Periocular dark circles may appear because of various anatomic factors such as architecture of facial ligaments, the bony facial structure, midface soft tissue including the prominence of the orbicularis oculi muscle. Because of ageing, there is a loss of facial fat leading to inflexible ligaments causing hollowing effect on orbital rim. There is worsening of shadowing due to hollowness, which is mainly seen in the tear trough area in inferomedial orbit. The thin eyelid skin contributes to the prominence of the underlying soft tissue and subcutaneous vascular network and the orbicularis oculi muscle, due to which the overlying skin appears dark.
Visible pigmentary changes in periorbital area may be due to extravasated hemoglobin and its breakdown products bilirubin and biliverdin. A variety of pathologic and age-related processes result in the increased permeability of the local vasculature resulting in these pigmentary changes. The lower eyelid tissues may have an increased tendency to accumulate fluid due to local processes such as atopy as well as systemic fluid retention and can be limited inferiorly by the orbital rim because of the cutaneous ligaments. This fluid often takes on a purplish color due to the prominent role of the orbicularis muscle in the lower eyelid. Medical disorders including disorders of liver, heart, thyroid or kidney, hereditary blood disorders, vitamin K deficiency, Addison disease, or circulatory conditions, which result in excess fluid retention, can also lead to POH. Postinflammatory causes for POH include atopic and allergic contact dermatitis as well as other dermatologic disorders.
Histopathologic examination reveals epidermal, dermal, or mixed pigmentation with no other significant changes. Special stains such as Fontana-masson silver stain for melanin and pearls potassium ferricyanide can help for hemosiderin deposits.
A classification of POH has been proposed by Huang et al., in which they classified 65 cases on the basis of woods lamp and ultrasonographic assessment into four types including pigmented (brown) (5%), structural (3%), vascular (blue to purple) (14%), and mixed type (subtypes: pigmented vascular, pigmented structural, vascular structural, and combination of three) (78%). Pigmented type is characterized by infraorbital brownish hue, vascular type appears as infraorbital blue, pink or purple hue with or without edema, structural type appears as shadows formed by anatomic contours which can be easily vanished by stretching the skin, and mixed type by the combination of above features.
In another proposed classification by Ranu et al., POH was classified as vascular, constitutional, postinflammatory hyperpigmentation, and shadow effects. They observed that vascular form (41.8%) was the most common variant followed by constitutional hyperpigmentation (38.6%) in Chinese population (Fitzpatrick skin I–IV), whereas constitutional was more common in Indian and Malays (Fitzpatrick skin V–VI). An Indian study has shown that among Indians, the most common cause is constitutional (51.5%) followed by postinflammatory (22.5%) and vascular (8%).
On dermoscopy, pigmented type POH, the pattern of multiple dots with different sizes and colors or a diffuse network of pigment is seen, whereas vascular type shows diffuse erythema or multiple thin blood vessels or diffuse vascular network. The mixed type shows the combination of the above-described patterns. Dermoscopy helps in the differentiation of cause of lesions as the treatment depends on etiology.
Eyelid stretch test can be used to differentiate the shadowing effect from other causes as stretching the eyelids leads to the disappearance of pigmentation effect.
Woods lamp examination also helps to differentiate epidermal, dermal, and mixed type pigment patterns.
A hand-held microprocessor controlled reflectance spectrophotometer can be used to assess the skin color. It provides the values of the erythema and melanin indices as a function of the absorbance characteristic of the human skin. As the skin becomes more erythematous and more pigmented, erythema and melanin index increase, respectively. Melanin index is mainly influenced by the melanin content. Melanin index can be used to monitor the treatment response.
An accurate etiologic classification is necessary for a better therapeutic approach. The treatment of POH can be broadly classified into medical and surgical therapies. A variety of topical depigmenting agents are in vogue nowadays with special formulation for treating POH.
Medical management
In vascular POH, the main treatment is to target the vessel walls to stabilize them, and the use of vitamin C, Phytonadione (vitamin K1), tretinoin and so on can help, whereas pigmented POH is treated with hydroquinone and other depigmenting agents, along with lasers. In mixed type POH, the approach should be through combination therapy.
Concealers and cosmeceuticals are the least invasive treatment options for POH. Optical diffusers are an important adjunct in the camouflage of dark circles around periorbital area. Retinoids are vitamin A derivatives that impact multiple pathways to decrease the appearance of dark circles in the infraorbital region. First, they promote collagen synthesis and promote the reorganization of collagen bundles to improve the skin turgor and quality. They also decrease melanin content and reduce the size of melanocyte.
Hydroquinone is a competitive antagonist for tyrosinase, which plays a critical role in the pigmentation pathway. A range of hydroquinone concentrations is available, typically through a compounding pharmacy. Using low concentrations around 2–6% hydroquinone is typically sufficient to achieve melanocyte stabilization as a means to decrease the pigment deposition in the periorbital region. Arbutin is a botanical extract with a structure very similar to hydroquinone and has demonstrated similar efficacy. Kojic acid also acts in blocking the tyrosinase pathway by binding to copper. Topical caffeine is an effective means of treating infraorbital dark circles. When applied topically, it can be an asset in treating the dark circles that result from subcutaneous vascularization, telangiectasias, and edema due to leaky vessels.
Physical and surgical management
Intense pulsed light (IPL), pulsed dye lasers, radiofrequency, and Q switched lasers have also been used with variable success. Other management options include chemical peeling agents, fillers, and fat transfer techniques and surgery.
Face is important aesthetically, and perceptions regarding a person’s age and fatigue are generally based on periorbital aesthetics, so POH has an impact on the patients’ quality of life. Although no published studies are there studying the severity with which the quality of life is affected, still as per experience, it does have significant psychological implications, especially among young females with type III and IV skin.