The objectives of this prospective crossover, open-label, nonrandomized study are to estimate effect sizes of vasodilatation and sense of warmth after application of topical rosemary essential oil in patients suffering from systemic sclerosis.

In a crossover design, patients suffering from systemic sclerosis (12 subjects) receive applications of olive oil and of 10% Rosmarinus officinalis L. (rosemary) essential oil to both hands with a wash-out period of 3 hours. Effects on vasodilatation are measured with infrared thermography. Patients' sense of warmth is assessed by the "Herdecke warmth perception questionnaire". Measurements take place at baseline and 45 minutes following the interventions (pre-post-comparison). To determine within and between-differences, 2-sample t-tests will be used and effect sizes will be calculated (Standardized Effect Size).

Inclusion Criteria:

• Systemic sclerosis with skin involvement of hands and fingers
• Raynaud phenomenon with frequent symptoms of cold hands

Exclusion Criteria:

• Topical treatment with nitroglyceride
• Lymphdrainage < 24 hours
• Other topical treatment of hands and arms < 4 hours prior to study intervention