الفهرس 
• Role of azithromycin in rosaceaOnly 14 pages are availabe for public view
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Abstract
Rosacea is a common chronic cutaneous disorder of unknown etiology which occurs most commonly in middle- aged individuals. Cutaneous manifestations include transient or persistent facial erythema, telangiectasia, edema, papules and pustules that are usually confined to the central portion of the face. There is strong evidence that rosacea is primarily an inflammatory disease. This view is supported by histopathologic findings that include follicular and perivascular leucocytic infiltrates and an absence of pathologic microflora. Also, the success of anti-inflammatory agents in the treatment of rosacea, suggests that inflammatory cells such as neutrophils, and other inflammatory mediators, are key pathophysiologic factors in the development of rosacea.
Molecular studies suggest that an altered innate immune response is involved in the pathogenesis of the vascular and inflammatory disease seen in patients with rosacea. The multiple factors that lead to a trigger of the innate immune system would explain the diverse findings in rosacea etiology and help to understand why the current therapies are effective.
Chlamydia pneumonia has the ability to cause persistent infections and the ability to disseminate via the vascular system. This organism has been associated with many inflammatory diseases, including atherosclerosis, multiple sclerosis, asthma, Alzheimer’s and other inflammatory disorders. Persistent C. pneumoniae infection of epithelial cells has been shown to produce chronic blood vessel inflammation, resulting in production of host of cytokines and growth factors such as those presumed to be found in rosacea.
C.pneumoniae might be one of the triggers of innate immune response in rosacea patients through stimulation of TLR2 which was shown to be abnormally expressed in rosacea patients.
Our study included 20 patients with rosacea and 10 healthy volunteers as controls. Chlamydia pneumonia DNA was detected using real time PCR in skin biopsies obtained from both cases and controls. TNF-α mRNA was also assessed in both groups’ skin biopsies. Patients were assigned to receive azithromycin as an antichlamydial drug for 4 weeks as monotherapy and skin biopsies were re-examined for C.pneumoniae DNA and TNF- α mRNA.
Statistical analysis of results revealed that 70% of patients had positive C.pneumoniae DNA vs 20% in the control group and this may point to a possible role for C.pneumoniae in the etiopathogenesis of rosacea. TNF-α mRNA was significantly elevated in patients than in controls which confirms the inflammatory nature of rasacea. However, there was no significant statistical difference in TNF-α mRNA gene expression between patients with positive C.pneumoniae DNA and those with negative C.pneumoniae DNA. This may be explained by infection of lymphocytes which show attenuated cytokine response upon persistent infection with C.pneumoniae. This could be also attributed to the persistent state of C.pneumoniae which may not be associated with active immune response .Also; other cytokines could be measured as IL-6, IL-8, IL-1, IL-12 and IFN-.
After treatment with azithromycin, there was a significant statistical improvement in inflammatory lesions even in patients with persistent C.pneumoniae DNA, however, erythema stages didn’t show significant difference. This may be due to the relatively short treatment period; and that erythema usually needs longer treatment period to improve. Chlamydia pneumoniae DNA was re-detected in 8 out of 14 positive cases and 6 cases turned negative after treatment. This could be attributed to the severity of some cases which may have needed longer treatment period especially that dosing and duration of antibiotics in chronic chlamydial infectios are not well established.
On the other hand, TNF-α mRNA decreased significantly in all cases treated even in those with persistent positivity for C.pneumoniae. This result confirms the anti-inflammatory action of macrolides(azithromycin)and suggests that success of azithromycin in rosacea is due to its anti-inflammatory effect more than its antichlamydial one as in the case for tetracyclines.