Quantitative Evaluation of Successful Combination Therapy With Dye Laser and Long‐Pulse Alexandrite Laser for Papulopustular Rosacea

Rosacea is a chronic skin disease characterized by facial flushing, dilated blood vessels, rashes, and swelling and has a significant impact not only on the patient's appearance, but also on their quality of life. Dye laser has the effect of contracting dilated blood vessels by selectively being absorbed in oxidized hemoglobin, and as a result, it improves flushing and dilated blood vessels. Dye laser is a useful option for erythematotelangiectatic rosacea (ETR). However, its effectiveness for papulopustular rosacea (PPR) is limited, and it is not recommended in several national guidelines. We examined the treatment effects of 28 cases diagnosed with rosacea and treated with dye laser therapy at Nagoya City University Hospital from April 2019 to March 2023. The cohort comprised 6 males, 22 females, 13 cases of ETR, 12 cases of PPR, and 3 cases of phymatous rosacea (PhyR). The evaluation was based on clinical photographs, and the redness and blueness of the skin were deconvoluted and quantified using ImageJ/Fiji software. In the case of ETR, there was a significant improvement between before and after treatment ( p = 0.039). In the case of PPR, there was no significant improvement in the five cases treated with dye laser alone ( p = 0.083). Still, there was significant improvement in the seven cases treated with a combination of long‐pulse alexandrite (LPA) laser ( p = 0.0024). A multiple logistic regression analysis was performed on the combined therapies other than LPA laser, including topical corticosteroids, tacrolimus, metronidazole, sulfur and camphor, azelaic acid, antibiotics, or vitamin B. No treatment was found to contribute to significant improvement. LPA laser is expected to reduce inflammation around hair follicles seen in PPR effectively, and its combination with dye laser is a promising treatment option for PPR. Furthermore, this quantitative method based on clinical photographs is useful for the objective evaluation of rosacea treatment.