Real‐World Outcomes and Safety of
JAK
Inhibitors in Paediatric Alopecia Areata: A Retrospective Multicentre Study
Miguel Mansilla‐Polo, Aniza Giacaman, Carlos Abril‐Pérez, Daniel Martín‐Torregrosa, Laura Berbegal‐de Gracia, Tania Díaz‐Corpas, Ainhoa Fernández‐Arregui, Javier Melgosa‐Ramos, Alberto Soto‐Moreno, Alejandra Ruiz‐Villanueva, Juncal Roca‐Ginés, Gerard Pitarch‐Bort, Altea Esteve‐Martínez, Ana Martín‐Santiago, Alonso García‐Núñez, José Bernabéu‐Wittel, María Teresa Monserrat‐García, Montserrat Évole‐Buselli ABSTRACT
Introduction
Alopecia areata (AA) is a non‐scarring, immune‐mediated hair loss disorder with substantial psychosocial impact in children. Robust paediatric real‐world evidence regarding Janus kinase inhibitors (JAKi) for this disease is limited. In this study, we describe real‐world clinical outcomes and safety of JAKi for paediatric AA.
Methods
We conducted a retrospective, observational multicentre study across 11 Spanish hospitals including patients aged 0–18 years who initiated a first JAKi (baricitinib, tofacitinib, or ritlecitinib) in routine care. The primary outcome was Severity of Alopecia Tool (SALT)‐50. Secondary outcomes included the absolute SALT trajectory, eyebrow/eyelash responses, adverse events, and switching to a second JAKi.
Results
Forty‐six patients were included (baricitinib 22/46 [47.8%], tofacitinib 14/46 [30.4%], ritlecitinib 10/46 [21.7%]; mean age 11.3 ± 4.0 years). Eight patients (21.6%) achieved SALT‐50 at weeks 4–8, 21 patients (58.3%) at week 16, 20 patients (80.0%) at week 48, and 14 patients (82.4%) at week 72. Eyebrow and eyelash responses improved concordantly. At week 16, higher baseline SALT reduced the odds of response (β = −0.061, SE 0.029; p = 0.034). Unadjusted response rates varied across drug groups; however, treatment allocation was non‐random, and groups were markedly imbalanced at baseline, so drug‐level comparisons are exploratory and likely confounded by indication. Response was lower in universalis (unadjusted p = 0.008). Adverse events occurred in 16 of 46 patients (34.8%), mostly mild, with two patients (4.3%) discontinuing treatment. A second JAKi was used in seven patients (15.2%): Three complete, two partial, and two absent responses occurred post‐switch.
Discussion
In real‐world paediatric practice, we observed improvements in scalp, eyebrow, and eyelash involvement with JAKi use, with a generally favourable tolerability profile. Given the observational design, baseline imbalances, and missing data, causal inference and between‐drug comparisons are not supported.