Folliculitis decalvans (FD) is a rare form of scarring alopecia, presenting with tufted hairs, follicular papules or pustules. It is the most common of neutrophilic alopecia, often associated with pruritus and pain. Currently, the cause of FD is still unknown. Scalp colonization by staphylococcus aureus seems to induce a severe inflammatory reaction with consequent destruction of hair follicles. All patients with active FD should be treated because the disease destroys hair follicles and causes permanent hair loss. Multiple treatments exist, but often provide only transitory or modest improvement. For this reason FD can negatively affect patient’s quality of life. A 46-year-old man presented with 15-year history of FD characterized by recurrent purulent follicular lesion on occipital side of the scalp and consequent scarring alopecia. His medical history was unremarkable, but he was distressed by the appearance of the lesions and hair loss. He was treated with different therapies such as doxycycline, rifampicin and hydroxychloroquine with poor results. He underwent two sessions of photodynamic treatment with methyl aminolevulinate at 2-week interval. At first, he was achieved benefit, but after 2 months there was recurrence and further progression of the disease. Based on literature reports, we decided to treat with long-pulse ND:Yag laser. We started at 30 J/cm2 and then we improved dose until 80 J/cm2. A total of 7 treatments in an 8-12 weeks inter-treatment interval were performed with successfully outcome, without relapse for more than 18 months of follow up. We monitored scalp inflammation with reflectance confocal microscopy (RCM) and optical coherence tomography (OCT) during patient’s treatment. Both technologies represent non-invasive diagnostic tool and their application on inflammatory skin diseases has increased in the last years. ND:Yag laser is useful therapy option in the treatment of recalcitrant FD. Our experience allowed us to monitor the evolution of inflammatory reaction, confirmed treatment’s efficacy over the clinical examination
