Reticular erythematous mucinosis (REM) is a rare, chronic skin disorder that mainly affects middle-aged women, presenting as erythematous papules in a reticulated pattern on the trunk.1 Histopathologically, it features mucin deposition in the superficial and mid-dermis, highlighted by Alcian blue staining. Its unclear pathogenesis may involve UV radiation, infections, and immune dysregulation. Due to its resemblance to other dermatoses, diagnosis is often delayed.2 Moreover, REM poses a therapeutic challenge. Standard treatments yield inconsistent results and are frequently associated with undesirable side effects. In light of these limitations, pulsed dye laser (PDL) therapy has emerged as a promising and safer alternative.

In this context, we report a case series of three patients with histologically confirmed REM who were referred to our laser dermatology unit after showing inadequate response to topical corticosteroids and hydroxychloroquine. Before initiating full treatment, a test area of 2cm2 was treated in each case using PDL 595nm (VBeam Prima®, Candela Medical Cooperation, United States), which demonstrated a favorable initial response. Subsequently, all patients received the treatment with the same laser.

All patients exhibited a rapid clinical response, with substantial improvement after only one to two sessions (Fig. 1). Treatment parameters included 0.5–2ms pulse durations, fluences of 7–8.5J/cm2, a 10mm spot size, and sufficient handpiece-to-skin distance to induce moderate persistent purpura, which was established as the clinical endpoint. Procedures were well tolerated without the need for anesthesia, and no significant adverse effects – such as bleeding, crusting, or scarring – were observed.

Fig. 1.

Clinical progression before and after laser treatment. (1) After 6 sessions: excellent response; currently on maintenance therapy every 6 months. (2) Very good response, no skin lesions after 5 laser sessions. (3) Remarkable improvement after a single session.

Treatment sessions were initially performed every 4–8 weeks, transitioning to maintenance sessions at six-month intervals. Two of the three patients continued receiving PDL monotherapy with sustained clinical control, while the third patient discontinued further sessions after achieving satisfactory improvement following five treatments. All clinical and therapeutic aspects of the cohort are detailed in Table 1.

REM remains a diagnostic challenge because of its rarity and overlap with other conditions such as lupus erythematosus tumidus (LET).3 Both share features like plaque-like lesions and photosensitivity; however, histopathologic and immunologic distinctions support their classification as separate entities.4,5 PDL appears to act similarly in REM and LET, primarily through selective damage to dermal blood vessels and activation of immune responses.1 Although these clinical effects are well documented, the underlying molecular and cellular mechanisms remain unclear. In our series, one patient remained misdiagnosed for over 8 years – initially labeled with folliculitis by multiple clinicians – highlighting the importance of heightened awareness and suspicion when evaluating reticulated papular eruptions on the trunk.

Currently, only a limited number of reports have addressed laser therapy in REM, with Greve et al.6 being the first to document favorable outcomes after 3–5 sessions in 2 patients. Our findings align with this, showing that PDL 595nm can provide rapid and sustained clinical improvement, often after just one or two sessions spaced 4–8 weeks apart. Achieving moderate purpura during treatment correlates with better outcomes, and maintenance sessions every 6 months may help prevent relapses.

In conclusion, REM is a distinct and underdiagnosed dermatologic condition. Therapeutic options for REM are limited and often based on case reports or small series. In this context, PDL 595nm seems to be a safe and effective therapeutic option for REM providing rapid and sustained clinical improvement with minimal, transient side effects. Compared to conventional systemic therapies (such as antimalarials), which often have delayed effects, significant side effects, and high relapse rates, PDL requires fewer sessions, has a low recurrence rate, and is well tolerated – even in refractory cases or patients with contraindications to systemic drugs. Its ease of repeatability further enhances patient adherence, making PDL a valuable and preferable option for managing REM.