Rosacea is a common disorder that is frequently mistaken for acne. In fact, as recently as 20 years ago, rosacea was referred to as “acne rosacea.” Both conditions look alike, they often respond to the same treatments, and often coexist.

Rosacea arises later in life than does acne, usually between 30 and 50 years of age and women are three times more likely to be affected than men.

Rosacea has been traditionally described as occurring predominantly in fair-skinned people from Great Britain (Scotland and Wales), Ireland, Germany, Scandinavia, and certain areas of Eastern Europe; however, a greatly underreported incidence of rosacea is also seen in Hispanic populations.

The precise cause of rosacea remains unknown, it is believed that multiple factors contribute to its development and progression, including:

• Genetic predisposition

• Defects in the skin's innate immunity (decreased cathelicidins)

• Overstimulation of cutaneous nerves and blood vessels

• Damage from ultraviolet light

• Demodex, a species of mite that is often found in the hair follicle

Rosacea is not caused by drinking excessive amounts of alcohol and does not appear to have any relationship to androgenic hormones.

Recognized environmental factors may trigger flushing and exacerbate rosacea.

Burning and flushing, in some patients, can become quite uncomfortable.

Patients may also have ocular involvement, typically blepharoconjunctivitis. They may complain of eye stinging, burning, dryness, photophobia, excessive tears, or a foreign body sensation. Episcleritis and keratoconjunctivitis sicca are rare complications.

Ocular rosacea may precede the skin manifestations in up to 20% of people.

Rosacea is diagnosed clinically.

A biopsy may be necessary in atypical cases.

Rosacea is a facial eruption that consists of acne-like erythematous papules, pustules, and telangiectasias.

At first, rosacea begins with erythema on the cheeks and forehead that later spreads to the nose and chin. This is referred to as erythematotelangiectatic rosacea.

As rosacea progresses, telangiectasias, papules, and sometimes, pustules begin to arise against a background of erythema and can be severe (Fig. 12.13). The papules and pustules (papulopustular rosacea) may tend to come and go, but the erythema and telangiectasias are likely to remain.

Lacks the comedones (“blackheads” or “whiteheads”) that are seen in acne and in general, no scarring or nodules/cysts are present (unless the patient has concomitant acne).

Ocular lesions include erythema of the lid margins and conjunctival injection (Fig. 12.14).

Lesions are typically seen on the central third of the face—forehead, nose, cheeks, and chin (the so-called “flush/blush” areas) (Fig. 12.15).

Lesions tend to be bilaterally symmetric, but they may occur on only one side of the patient's face.