Advances in the topical treatment of acne and rosacea

Journal of Drugs in Dermatology, Sept-Oct, 2004 by Roger I. Ceilley

The patient should be questioned regarding what triggers and what palliates symptoms. Triggers have great inter-patient variability. A recent survey of 1066 patients was conducted by the National Rosacea Society identified the most frequent rosacea triggers (Table 6) (36).

The physician should assess the presence and type of lesions and their associated secondary features. The differential diagnosis of rosacea most commonly includes acne, seborrheic dermatitis, perioral dermatitis, carcinoid syndrome, and lupus erythematosus (Table 7).

Table 8 lists some of the neurologic and systemic factors and diseases that might cause the symptoms of rosacea.

Management of Rosacea

Rosacea is not a disease with a cure. There is not currently for rosacea a panoply of rational therapies developed from a thorough understanding of its etiology and targeting known pathogenetic factors. However, it is manageable with a combination of lifestyle measures to reduce exposure to known triggers, topical and systemic medications tailored to the disease manifestations and light therapies.

In addition to avoiding known triggers, rosacea patients should practice assiduous sun avoidance and use a high SPF broad-spectrum sunscreen. Physical sunblocks, such as titanium dioxide and zinc oxide, are particularly useful for erythemic rosacea patients. Rather than converting light energy to heat energy in the skin which could exacerbate the erythemic response, they scatter light before it penetrates the skin.

Topical and systemic therapies are chosen based on the type and severity of the rosacea. For all but the most mild manifestations, initial rosacea treatment often includes an oral antibiotic to help alleviate erythema and gain control of inflammatory lesions. Table 9 lists the first- and second-line oral antibiotics used in rosacea management.

Typically, papules, pustules and sometimes nodules and plaques respond rapidly and completely to systemic tetracyclines. If not, agents from the second tier may be tried. Telangiectasia and phymatous changes are unaffected by systemic antibiotics.

Topical metronidazole, an imidazole with anti-inflammatory and antimicrobial effects is considered the workhorse of topical rosacea therapies and is the most widely studied therapy. Its mechanism of action in rosacea is unclear. It has been suggested that its effects in rosacea may be related to inhibition of neutrophil-generated inflammatory mediators and free radicals (37,38). Metronidazole is effective against papules and pustules and may, in some patients, reduce erythema. Similar to other topical therapies and oral antibiotics, it is rarely effective for telangiectasias.

Since rosacea is a recurring and potentially progressive disease. maintenance therapy is essential following initial systemic antibiotic use or light- or laser-based therapy. Topical metronidazole has been shown to be effective in maintaining remission. In a 2-phase study, patients who were initially treated with systemic tetracycline in combination with topical metronidazole, were later included in a blinded 6-month study comparing metronidazole gel 0.75% [Metro[R] Gel] to placebo vehicle. Topical metronidazole was significantly superior to vehicle in maintaining remission (43% relapsed vs 23% relapsed) and in reducing lesion counts. Relapse of erythema was also less frequent in patients treated with metronidazole (74% vs 55%) (39). Metronidazole is available as a cream [Metro[R] Cream 0.75%, Noritate[R] 1%], gel [Metro[R] Gel 0.75%] and lotion [Metro[R] Lotion 0.75%]. It is generally well tolerated at both dosages and in all three formulations.