The investigators aim is to investigate the incidence of headache and rosacea-like flushing after pituitary adenylate cyclase-activating peptide-38 (PACAP38) with and without treatment with sumatriptan in patients with rosacea

Pituitary adenylate cyclase-activating peptide-38 (PACAP38) plays a role in rosacea pathophysiology. Infusions of PACAP38 can trigger migraine-like attacks in migraine patients. PACAP38 also induces flushing which may imitate rosacea-like flushing. We are investigating whether the flushing after PACAP38 resembles rosacea-like flushing, and whether treatment with sumatriptan has an effect on the headache and flushing effects of PACAP38.

The purpose of this study is to investigate PACAP38-induced headache and flushing in patients with rosacea who have been treated with either sumatriptan or placebo using purpose-developed standardized interview. The investigators will use a double-blind, placebo-controlled crossover study design to investigate this.

Inclusion Criteria:

• diagnosed with rosacea
• weight between 50 - 100 kilograms
• women in fertile age must not be pregnant and must use adequate contraception

Exclusion Criteria:

• migraine more than 5 days per month in average over the past year
• any primary headache other than migraine, apart from tension-type headache which must be less than 5 days per month
• headache < 48 hours before experimental day
• migraine < 72 hours before each experimental day
• daily / frequent use of any medication apart from contraceptive medication
• use of any drug less than 5 times the half-life of the drug at the time of the experiment
• women who are pregnant or breast-feeding at the time of the experiment
• anamnestic or clinical signs of hypertension (systolic blood pressure > 150 mmHg and/or diastolic blood pressure > 100 mmHg) or hypotension (systolic blood pressure < 90 mmHg and/or diastolic blood pressure < 50 mmHg)
• anamnestic or clinical signs of mental illness, or abuse of alcohol / drugs
• patients with glaucoma or prostate hyperplasia
• anamnestic or clinical symptoms of any sort that the investigating doctor deemed unfit for participating in the study

Double-blind