The goal is to evaluate the efficacy and safety of tofacitinib in treating refractory prurigo nodularis.The main questions it aims to answer are

1. whether tofacitinib is effective in treating prurigo nodularis in the longpterm.
2. whether tofacitinib is safe in prurigo nodularis patients in the longpterm.

Inclusion criteria:

1. age ≥18 years old;
2. patients diagnosed with PN with a duration of more than 6 months;
3. presence of at least 10 pruritic nodules;
4. a Worst Itch-Numeric Rating Scale (WI-NRS) score ≥7 one week before study;
5. a history of more than 2 weeks of ineffective topical glucocorticoid treatment or antihistamine therapy;
6. signed informed consent and cooperated with the follow up and complied the study protocol.

Exclusion criteria:

1. current used of biologic, systemic glucocorticoid or immunosuppressive agents; past used of jak inhibitors;
2. were pregnant or lactating;
3. abnormal findings for patients' complete blood count, liver functions, and kidney function tests;
4. presence of any infection or inflammatory; presence of active tumors or an increased risk of tumor complications；
5. systemic comorbidities that could interfere with or complicate study assessments.
6. those experiencing atopic dermatitis within 6 months were excluded from this study.

The data that support the findings of this study are not publicly available due to the privacy of research participants but are available from the sponsor upon reasonable request.