Itching is a common symptom encountered in general medical practice. It can cause significant discomfort, disrupt sleep, and impair patients' quality of life. Chronic pruritic skin conditions such as atopic dermatitis, nummular eczema, lichen simplex chronicus, and prurigo nodularis are frequently observed. The pathogenesis of these conditions remains incompletely understood, and effective long-term treatment options are limited. Current therapies include topical corticosteroids, topical calcineurin inhibitors, oral corticosteroids, and systemic immunosuppressants. However, these treatments are often associated with adverse effects, and the diseases tend to follow a chronic, relapsing course. Therefore, the investigators aim to investigate the efficacy and safety of topical cannabis extract in patients with chronic pruritic skin conditions.

Inclusion Criteria:

1. All participants must be aged 25 years or older.
2. Patients must be diagnosed with eczema, including atopic dermatitis, nummular eczema, lichen simplex chronicus, or prurigo nodularis, with pruritus persisting for more than 6 weeks.
3. Patients must be willing to refrain from using other topical products throughout the 4-week study period.
4. Patients must provide written informed consent to participate in the study.

Exclusion Criteria:

1. Patients who have taken oral steroids, immunosuppressive drugs, or received phototherapy within the past 3 months.
2. Patients with chronic kidney disease, liver cirrhosis, cancer, or thyroid disease.
3. Pregnant or breastfeeding women, or women planning to become pregnant.
4. Patients who develop erythematous itchy rash in response to an open patch test using cannabis extract products.
5. Patients with a known allergy to cannabis-derived products, which may result from other ingredients and/or solvents used in the extraction process.
6. Patients with severe or unstable cardio-pulmonary diseases (e.g., angina, peripheral vascular disease, cerebrovascular disease, or arrhythmia), or those at risk of cardiovascular disease.
7. Patients with a history of psychosis, current active mood disorder, or anxiety disorder.
8. Patients who are addicted to substances, including nicotine, or are heavy alcohol users.
9. Patients using other medications, particularly opioids or sedatives such as benzodiazepines.
10. Patients taking medications known to potentially interact with cannabis extracts, such as warfarin, fluoroquinolones, or dihydropyridine calcium channel blockers.