Erythrodermic Psoriasis: Excellent Management Avoiding Hospitalization.

Erythrodermic psoriasis (EP) is a rare but severe variant of this inflammatory cutaneous disease, occurring in less than 3% of patients with psoriasis. It is characterized by involvement of more than 90% of body surface area (BSA), with diffuse scaling and erythema. Usually, EP develops in subjects with poor control of psoriatic disease (1). EP is considered an emergency condition in dermatology due to extensive skin involvement and systemic symptoms; moreover, it is often resistant to conventional therapies (1,2). While the pathogenesis of plaque psoriasis is well-understood, with a complex interplay between Th1, Th2, and Th17 responses, the inflammatory mechanisms of EP are less known, but the IL-17 pathway seems to play a pivotal role (2). Brodalumab is a fully human monoclonal antibody blocking the interleukin-17 receptor A, thus interfering with different isoforms of IL-17 (A, A/F, F, C, and E) (3). This results in a complete block of the IL-17 response, including IL-17 C and E, which are released by keratinocytes and not directly by the Th17 line. Therefore, brodalumab presents a broader action in comparison with anti-IL-23 and other anti-IL-17 drugs, which act upstream on the Th17 line (4). As shown by Yamasaki et al. in a 52-week open-label study, brodalumab is associated with a rapid response, even in patients with EP, showing a drastic improvement in symptoms after just two weeks (3). Herein we report a case of a 57 -year-old woman with a recent diagnosis of plaque psoriasis, naïve to systemic therapies, who rapidly developed EP. Psoriasis diagnosis was confirmed by skin biopsy. With regard to comorbidities, she presented a history of excessive alcohol use and tested positive for latent tuberculosis. At the first evaluation, the patient presented with BSA involvement of 90%, a PASI score of 42, and a DLQI of 26, without psoriatic arthritis (Figure 1, a). At the examination, a concomitant ocular involvement was particularly evident, with conjunctival redness and a reported burning sensation (Figure 1, b). After receiving prophylactic treatment for latent tuberculosis, brodalumab was initiated at the labeled dosage. A dramatic improvement was observed after just two weeks, with a reduction of erythema and scaliness as well as the itching and burning sensation (Figure 2, a). Furthermore, the conjunctive redness completely disappeared. After 4 weeks, the PASI score was reduced to 2 and BSA decreased to 5%, with a positive impact on quality of life (Figure 2, b). The patient did not report any adverse events. Due to the rarity of this form of psoriasis, international guidelines or recommendations on EP treatment and management are lacking. Several biologic drugs are currently being used off label based on case reports or small case series, with an optimal response and tolerance profile (1). To our knowledge, , there have been only six cases of EP treated with brodalumab in real-life settings (2,4,5). Our experience, in accordance with the cases published in literature, showed a rapid onset of action, without any relevant adverse events. One of the most promising aspects of brodalumab in EP is the reduction in the hospitalization of patients; in fact, thanks to the rapidity of its action it is possible to avoid the administration of systemic steroid therapy, frequently used in the management of EP, and therefore avoid steroid-related AEs. Furthermore, it can be used in monotherapy due to its high efficacy, without conventional immunosuppressive drugs. Finally, its excellent tolerance profile allows its use in a wider patient setting. In conclusion, brodalumab could represent a valid therapeutic option for EP, based on its clinical efficacy, rapid effect, and safety, especially considering the reduction of the clinical burden for both patient and hospital management.