Adalimumab biosimilar in a pediatric patient: Clinical and in vivo reflectance confocal microscopy evaluation

Dear Editor, Psoriasis is a chronic inflammatory skin disease, with a prevalence of 1%–5%. The scalp is the most frequently affected area, up to 79%. Nail psoriasis is also common, involving about 50%. The effectiveness of adalimumab for nail and scalp psoriasis has been demonstrated. Indeed, patients treated with adalimumab, anti-TNFα monoclonal antibody, have reached an improvement of Nail Psoriasis Severity Index (NAPSI) of 60% and of Psoriasis Scalp Severity Index (PSSI) of 100% at week 16, respectively. In vivo reflectance confocal microscopy (RCM) performs a noninvasive, real-time evaluation of the skin, from the epidermis to the papillary dermis, being therefore a useful tool to analyze psoriasis treatment response. RCM has been employed in different dermatologic conditions, such as skin cancers, and inflammatory skin conditions. We herein report the first pediatric case of scalp and nail psoriasis, successfully treated with adalimumab biosimilar, followed with dermoscopic and RCM examination. A 16-year-old male patient with moderate-to-severe psoriasis refractory to topical treatment and cyclosporine was referred to our department. Clinical examination showed psoriatic lesions, mostly on scalp, palms, soles, and severe nail involvement (Figure 1A,C) [Psoriasis Area Severity Index (PASI) = 8.6, body surface area (BSA) = 9.5, PSSI = 30, and NAPSI = 160]. Eighty percentage of scalp area and 20% of palms and soles were affected. Dermatoscopic evaluation revealed glomerular vessels and whitish interfollicular scales surrounded by an erythematous background in scalp lesions (Figure 1E) while pitting and multiple splinter hemorrages were found in nails (Figure 1G). RCM of nail lesions revealed delamination of the nail plate presenting as hyperreflective areas and hyporeflective circles that likely correspond to nail pitting (Figure 1K). Moreover, RCM of the scalp revealed parakeratosis, atypical, honeycombed pattern, and inflammatory cells on the superficial layer, and the presence of papillomatosis with hypervascularization at the dermal-epidermal junction (Figure 1I). Due to failure of previous therapies, the patient was screened for biological treatment. Adalimumab biosimilar was chosen due to the indication after 4 years of age and efficacy in nail and scalp psoriasis. At 12-week follow-up, significant improvement was observed. PASI75 (75% reduction of baseline PASI) and PSSI90 (90% reduction of baseline PSSI) were achieved, BSA decreased to 1%, and NAPSI to 14. RCM confirmed the improvement of scalp and nails conditions but failed to show a normal conformation. At 24 weeks, PASI100 was achieved, and nail psoriasis completely resolved (NAPSI = 0) (Figure 1B,D). RCM confirmed resolution of the lesions with a return to normal dermal papillae configuration with a rim of bright basal keratinocytes and a normal display of the nail plate with some stellate figures corresponding to epidermal keratinocytes sectioned obliquely and regular honeycombed pattern of the epidermis (Figure 1J,L). Psoriasis resolution was confirmed at dermoscopy which did not reveal any alteration (Figure 1F,H). Nail and scalp psoriasis are difficult to treat and cause severe quality of life impairment. The evaluation of psoriasis severity through RCM is a useful tool to investigate not only clinical but also subclinical changes, as suggested for the first time by Ardigò et al. in 2013. Then, a recent study tried to evaluate the RCM improvement of 48 patients with psoriasis, but scalp and nails lesions were excluded from the assessment. To the best of our knowledge, this is the first case of an adolescent patient with nail and scalp psoriasis successfully treated with adalimumab biosimilar and followed by RCM evaluation. RCM is a promising instrument for monitoring nail and scalp psoriasis. RCM provides the means for an early diagnosis, even before clinical manifestations, making a timely therapeutic intervention possible. Also, it helps evaluate therapeutic efficacy and the need of treatment continuation even when clinically a complete response has been found. It is a useful tool for the detection of early phases of the disease and for therapeutic monitoring.