This is a single-centre, randomised, vehicle-controlled, double-blind, within-subject comparison phase 1 clinical trial. The trial is designed to find out if delgocitinib cream can cause skin irritation after light exposure in people with healthy skin.

Key Inclusion Criteria:

• Healthy subjects aged 18-64 years (inclusive).
• Fitzpatrick skin type of I, II, or III.

Key Exclusion Criteria:

• Atopic dermatitis, eczema, psoriasis, acne, dermatitis solaris or suntan that could interfere with the test field evaluation, hyperpigmentation, multiple naevi, tattoos, blemishes or dense body hair in the range of the test fields.
• Any history of or presence of cancerous or precancerous skin lesions.
• Any other skin disease or other visible skin condition noted on physical examination which in the investigator's opinion might interfere with the evaluation of the test field reaction.
• Known disease that can be induced by ultraviolet (UV) light.
• Use of any topical or systemic medication which could interfere with the trial objective within 2 weeks before randomisation until end of trial.
• Use of drugs which might cause photobiologic or phototoxic reactions within 4 weeks before randomisation until end of trial.
• Foreseeable intensive UV light exposure (solar or artificial) to test fields within 4 weeks before randomisation until end of trial.