A study of the pathogenesis of rosacea: how angiogenesis and mast cells may participate in a complex multifactorial process.

In the present study we evaluated, in involved and clinically uninvolved skin of Rosacea, microvessels density (MVD) and total vascular area (TVA) in addition to multiple morphologic characteristics of microvessels and also mast cells (MCs) number. We examined also the relationship between angiogenesis, MCs number and disease clinicopathological data. The study included 69 patients with Rosacea. A skin biopsy with a 4-mm punch was performed from clinically involved skin in each case. In nine randomly selected patients, facial biopsy specimens were obtained from both involved and clinically uninvolved skin. Histological sections, immunostained for factor VIII, were evaluated by image analysis for the quantification of MVD, TVA and several morphometric parameters related to the vessel size or shape. MCs detection in the dermis was carried out using the chloracetate esterase method (Fast Blue RR) in parafin sections. Serum antibodies against H.pylori were detected. Statistically important differences concerning the factors of angiogenesis between lesional and clinically non-lesional skin were demonstrated. A statistical important correlation was found also between high vascular density, PPR clinical type and the presence of ocular manifestations. MVD or TVA showed no correlation with the degree of solar elastosis or inflammation and with the Demodex density as well. However, high MVD values were found to correlate with granuloma formation in the dermis. MCs number were significantly greater in lesional compared to clinically non-lesional skin. Statistical significance was shown between MCs density and disease duration. However, no correlation between MCs number and blood vessel density was found. Angiogenesis seems to play an important role in the pathogenesis especially of the more severe clinical form of Rosacea. MCs seem to participate in evolution to disease chronicity by contributing to inflammation, angiogenesis and tissue fibrosis.

Rosacea: a clinicopathological approach.

BACKGROUND: There are few reports of the histological changes in rosacea, and little attempt has been made to correlate such changes with clinical findings. In the present study, we describe in detail the histopathological features of rosacea in a large number of patients and simultaneously investigate the aetiopathogenesis of the disease based on the comparative assessment of epidemiological, clinical and histological findings. METHODS: The study included 73 patients with rosacea. A skin biopsy with a 4-mm punch was performed in each case. All biopsy specimens included subcutaneous tissue. In 10 randomly selected patients, facial biopsy specimens were obtained from both involved and uninvolved (non-lesional) skin. Demodex mite presence was estimated semi-quantitatively under light microscopy. Patients with self-reported gastro-intestinal symptoms were submitted to upper gastro-intestinal endoscopy, and a rapid urease test was performed. Serological antibodies, IgG and IgA, against Helicobacter pylori were also detected. RESULTS: The patients had a broad clinical spectrum of lesions. No specific histological features associated with either erythematous-telangiectatic or papulopustular clinical forms were noticed. Histological examination showed that there is no histological pattern unique to rosacea. Three different types of granulomas were observed: small palisaded ones around altered collagen and other granulomas of elastolytic and non-specific epithelioid type, all coexisting in 5 cases. The deep dermis and subcutis were frequently involved. Comparative study in 10 rosacea patients between lesional and non-lesional skin biopsies revealed almost the same histological changes to the latter biopsies, to a lesser degree though. CONCLUSION: Rosacea seems to be a reaction pattern to which a variety of pathogenetic routes may lead.