The goal of this clinical study is to investigate the effects of systemic isotretinoin on vasoactive neuropeptides (PACAP, VIP, CGRP) and its relationship with the erythema index in patients with rosacea. It also aims to assess the clinical efficacy of isotretinoin in reducing rosacea severity. The main questions this study seeks to answer are:

Does systemic isotretinoin treatment lead to changes in PACAP, VIP, and CGRP levels in rosacea patients? How does isotretinoin affect erythema and overall rosacea severity? Researchers will compare pre- and post-treatment neuropeptide levels and erythema index measurements to determine the effects of isotretinoin.

Participants will:

Take 0.3 mg/kg/day of isotretinoin for three months Undergo monthly clinical evaluations with RASI and erythema index measurements Have blood samples collected at baseline and after treatment to assess changes in PACAP, VIP, and CGRP levels

This clinical study investigates the effects of systemic isotretinoin on vasoactive neuropeptides (PACAP, VIP, CGRP) and its relationship with erythema severity in rosacea patients. The study aims to explore the potential role of these neuropeptides in rosacea pathogenesis and assess isotretinoin's impact beyond its known effects on papulopustular lesions.

A total of 30 patients with papulopustular rosacea (PPR) and 35 healthy controls are included in the study. Participants are evaluated before treatment and at the 1st, 2nd, and 3rd months of isotretinoin therapy. Lesion severity is assessed using the Rosacea Area and Severity Index (RASI), while erythema is objectively measured with a Mexameter device. Blood samples are collected at baseline and after three months of treatment to determine PACAP, VIP, and CGRP levels.

The study is designed to provide an objective assessment of neuropeptide levels in relation to erythema severity in rosacea and to explore potential mechanisms underlying isotretinoin's effects. Findings from this research may contribute to further investigations into VIP-targeted therapeutic strategies for erythema management in rosacea.

Inclusion Criteria:

• Patients aged 18 to 75 years with a diagnosis of papulopustular rosacea (PPR)
• No history of systemic or topical medication use for rosacea or other dermatological conditions in the past four weeks
• No known autoimmune or dysregulated systemic disease
• No history of migraine, inflammatory bowel disease or malignancy
• No daily sun exposure exceeding three hours
• No excessive spice consumption (more than three times per week)
• Non-smokers
• No excessive tea or coffee consumption (more than three times per week)
• Non-alcohol consumers
• No contraindications for systemic isotretinoin treatment

Exclusion Criteria:

• Patients younger than 18 or older than 75 years or without a diagnosis of papulopustular rosacea (PPR)
• History of systemic or topical medication use for rosacea or other dermatological conditions in the past four weeks
• Presence of a known autoimmune or dysregulated systemic disease
• History of migraine, inflammatory bowel disease, or malignancy
• Daily sun exposure exceeding three hours
• Frequent spice consumption (more than three times per week)
• Smokers
• Excessive tea or coffee consumption (more than three times per week)
• Alcohol consumers
• Presence of contraindications for systemic isotretinoin treatment