INTRODUCTION
Riehl melanosis is a rare cause of skin hyperpigmentation that typically occurs on the face and neck and is characterized by the rapid onset of gray-brown reticular pigmentation. The condition was first described in 1917 by Riehl and was dubbed “war melanosis†as it became more prevalent in Vienna during the First World War.1 In later reports, it has been theorized to be a pigmented contact dermatitis caused by fragrances, pigments, or bactericides found in common cosmetics.2 More recently, it has been postulated that Riehl melanosis is a lichenoid immune reaction that may be caused by intrinsic as well as extrinsic factors. 3, 4 The efficacy of reported treatments has been less than optimal. Reported therapies have included oral Vitamin C, topical bleaching products, and sun protection.5 Intense pulsed light (IPL) therapy is a common treatment for other pigmented skin conditions and has been reported twice for the treatment of Riehl melanosis.6, 7 We report the a case of Riehl melanosis successfully treated with a q-switched (Qs) frequency-doubled (FD) Nd:YAG laser after proving recalcitrant to IPL.
CASE REPORT
A 74-year-old woman presented to the clinic for evaluation for facial discoloration. She reported a 2-year history of brown discoloration on her cheeks that was progressing centripetally to her temples, forehead, eyelids, and chin. Prior to this eruption, she stated that she had only had a few freckles and on her face. She had used multiple over-the-counter lotions and tretinoin 0.05% cream with no improvement. She did not report a past or current use of cosmetics.
On examination, she had gray-brown macules and reticulated patches on her cheeks, forehead, temples, and chin as well as open comedomes on her cheeks (Figure 1). A shave biopsy was performed from the left temple and pathology demonstrated lentiginous pigmentation along the basal layers of the epidermis with underlying solar elastosis and with a few melanophages (Figure 2). Given this information along with her clinical presentation, she was felt to have Riehl melanosis rather than solar lentigines or melasma.
At this time, given her failure with topical therapy, it was decided that laser therapy would be attempted. Anesthesia with lidocaine 4% cream (LMX4, Ferndale Pharmaceuticals) was performed prior to all treatments. All treatments (Table) were performed using an IPL platform (Harmony, Alma Lasers, Buffalo Grove, Illinois) with a variety of filters. A variety of filters and settings were utilized on limited areas of skin to determine effective setting for full-face treatment. Her first three treatments were disappointing either due to a lack of effect or adverse reaction so her fourth treatment was performed with Qs FD Nd:YAG handpiece. She noticed a mild reduction in pigmentation in the treated area. The Qs FD Nd:YAG handpiece was repeated one month later with an increase from 400mJ to 800mJ, with one pass performed on the left cheek and temple. She again reported a minimum of adverse effects and mild improvement so one month later the same filter and settings were used on a larger area of the left forehead, cheek, and chin. The patient failed to return for her fourth scheduled treatment. She returned to the clinic two months after her previous treatment. Upon her return, she reported she had skipped her previous appointment because the hyperpigmentation had suddenly and remarkably improved and she did not feel she needed another treatment. Interestingly, areas not treated with laser therapy had also improved significantly (Figure 3). A post-treatment biopsy was not performed.
