The pilosebaceous glands in the affected skin are often involved and may enlarge. Exposure to sun and heat may cause exacerbations. The greatest incidence is in white women between the ages of 30 to 50 years. A food connection has also been implicated and standard Rosacea advice has included abstinence from alcohol, coffee, tea, and spices that cause flushing.
Standard treatment involves oral and topical antibiotics - usually metronidazole cream or gel.
The response to antibiotic treatment is partial at best and seldom cures the condition. The role of infection has never been determined. The response to metronidazole suggests that bacteria may play a role in perpetuating the inflammation but do not necessarily cause the disease. Inflamed skin tends to support more vigorous microorganism growth and nonpathogenic bacterial and fungi may become more invasive and pro-inflammatory. This is the situation in eczema caused by food allergy and many cases of psoriasis where topical antifungal treatment is sometimes helpful.