Comedones Induced by Vascular Laser Therapy

INTRODUCTION

Comedone formation due to laser therapy has not been described before. Here, we report a case of atrophic scars studded with open comedones, developing shortly after Nd-YAG laser (1071 nm) therapy used for facial telangiectasia.

CASE REPORT

A 21-year-old female presented with acne-like blackheads on brownish areas located on the cheek, which where recently treated with laser therapy. The patient had constitutional bilateral facial erythema and telangiectasia. She had been treated with neodymium-doped yttrium aluminium garnet (Nd-YAG) laser (1071 nm), 160 j/cm², 3 months ago. Immediately after treatment, marked facial redness and edema developed, most prominently on the right cheek, followed a few days later by small areas of dark scabbing. The reaction spontaneously subsided in about a week, but soon afterwards developed depressed areas with blackheads. She applied wet cold dressings with tap water and put silver sulfadiazine cream twice a day for 1 week after the laser treatment. She was not on any oral or topical medication before the laser treatment. Dermatological examination revealed facial erythema and telangiectasia involving both cheeks and zygomatic areas. There were atrophic, slightly depressed, hyperpigmented 3-4 mm scars with superimposed tiny comedones on the right cheek [Figure 1]. Dermoscopic examination clearly demonstrated the grouped comedones strictly confined to atrophic lesions [Figure 2]. Topical treatment with tretinoin 0.05% cream was commenced on alternate days and Sun Protection Factor (SPF) 50 sunscreen daily. After 2 months, comedones and hyperpigmentation resolved, and though atrophy persisted, it was more superficial than before [Figure 3].

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Figure 1

Hyperpigmented, slightly atrophic macules with overlying open comedones

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Figure 2

Dermoscopic examination clearly shows closely grouped comedones

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Figure 3

Two months after treatment with topical tretinoin cream. Comedones have disappeared, but atrophy persists

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DISCUSSION

Comedones are among the main features of acne vulgaris and results from abnormalities in the proliferation and differentiation of ductal keratinocytes.[1] Physical factors including chronic sun exposure and radiotherapy may induce comedone formation as well.[23] Favre-Racouchot disease, known as solar comedones, is thought to be caused by chronic exposure to ultraviolet light (UV). It is usually seen in people older than 50 years of age and besides comedones, clinical manifestations usually include solar elastosis and cystic nodules on the exposed areas of the face. It is hypothesized that UV damage to the dermal elastic network initiates pathologic events leading to changes of follicles.[2] In favor of this, there are additionaly some reports describing comedones overlying granuloma annulare lesions on the exposed areas.[4] Elastic and collagen fiber damage are the main accompanying features of granuloma annulare.[5] The loss of elastic fibers seen both in granuloma annulare and solar elastosis is speculated to cause the appearance of open comedones. Lacking the supporting properties of the dermis, infundibular canal of the sebaceous follicle might have distended, leading to the formation of comedones.[4]

There are a limited number of reports describing a Favre-Racouchot-like disease that developes after radiotherapy, with lesions restricted to the irradiated area.[2] Similar to UV, ionizing radiation might induce chronic follicular inflammation with secondary follicular hyperkeratosis, alterations of connective tissue support, and the production of comedones.

CONCLUSION

Several cutaneous complications of vascular laser therapy for telangiectasias have been reported. Among these, erythema, edema, purpura, hyper- and hypopigmentation, blistering, atrophic, or hypertrophic scars are well-known.[6] Through the literature search, we have not been able to find a case in which comedones developed after local trauma, induced by vascular laser therapy. However, some recent reports have described Fox-Fordyce-like disease following laser hair removal, appearing on the treated areas.[78] One of these cases was treated with alexandrite laser (755 nm), and the other with diode laser (800 nm). Fox-Fordyce disease is an inflammatory disorder of apocrine glands, and caused by infundibular keratinization and subsequent apocrine duct obstruction. Dilation of the follicular infundibulum with hyperkeratosis and keratin plugging is a common feature of this disorder. In the abovementioned cases, laser therapy might have induced damage to the follicular infundibulum, causing altered maturation of keratinocytes that led to keratin plugging which resulted in comedones.

In our patient, the fact that the comedones were confined to the depressed areas due to laser trauma, suggests a close relationship between comedones and laser effects. A possible explanation for this relationship is that the edema and inflammation caused by the laser therapy might have predisposed to follicular degeneration and retention of hyperproliferating ductal keratinocytes, which resulted in a keratin plug. In addition, posttreatment atrophic scarring with loss of elastic and collagen fibrils might have played a role in the formation of comedones.

In conclusion, we suggest that laser therapy is another physical factor that induces comedones. Comedone formation, associated with atrophic scars should be included in the complications of laser therapy for vascular lesions.