Rosacea is a common chronic inflammatory facial dermatosis characterized by erythema, telangiectasias, and an acneiform papulopustular eruption. It is most commonly seen in Caucasian individuals, particularly those from Celtic and Northern European backgrounds, ranging in age from 30 to 70 years old; however, it can affect all ethnic groups. There is a spectrum of clinical features. Progression may be stepwise and range from minor cosmetic changes to severe disabling facial features. Although rosacea is less common in skin of color, it is not rare (Alexis 2010). A recent study by Al Dabagh et al analyzed the National Ambulatory Medical Care Survey of 1993–2010 for racial and ethnic distribution of patients with rosacea. Rosacea was the primary diagnosis for 8.3 % of whites and 2.2 % of blacks (Al-Dabagh et al. 2014).

There are four main types of rosacea. Erythematotelangiectatic rosacea is characterized by erythema, central facial flushing, and telangiectasias. This may be accompanied by burning or stinging, which is often exacerbated when topical agents are applied. Papulopustular rosacea is also characterized by erythema of the central portion of the face, as well as small erythematous papules surrounded by pinpoint pustules (Fig. 2.1a, b). Phymatous rosacea is characterized by marked glandular thickenings and irregular surface nodularities of the nose, chin, forehead, ears, and the eyelids. Ocular rosacea can also occur and is characterized by blepharitis, conjunctivitis, inflammation of the lids, and conjunctival telangiectasias. Patients may describe eye stinging or burning, dryness, or irritation with light. Ocular manifestations may precede the cutaneous signs by years (Crawford et al. 2004).

The symptoms that lead to the diagnosis of rosacea are commonly documented as facial flushing, erythema, telangiectasias, skin sensitivity, and an acneiform papulopustular eruption. However, these symptoms do not always appear as such on skin of color. Because erythema and telangiectasias may be more difficult to appreciate in darker skin and less cosmetic deformity may occur in early cases, many cases of rosacea amongst people with skin of color may go undiagnosed and possibly contribute to fewer physician visits (Al-Dabagh et al. 2014). Therefore, physicians should consider the diagnosis of rosacea when patients with skin of color present with facial flushing, warmth, ocular symptoms, and a papulopustular eruption of the central face.

The exact cause of rosacea is unknown. However, several factors likely play a role in its development, including changes in vasculature, climactic exposures, chemicals and ingested agents, and microbial organisms. Erythema and flushing are likely secondary to vasodilatation and increased blood flow to facial blood vessels. Harsh climatic exposures, for example extremely hot or cold temperatures or wind exposure, may also damage cutaneous blood vessels (Laquer et al. 2009). Spicy foods, alcohol, hot beverages, exercise, topicals that irritate the skin, and medications that cause flushing are traditionally thought to trigger flushing in patients with rosacea (Crawford et al. 2004). Demodex species (mites that normally inhabit human hair follicles) may also play a role in the pathogenesis of rosacea. Some studies suggest that Demodex prefers the skin regions that are affected in rosacea, such as the nose and cheeks (Bonnar et al. 1993). Studies have also shown that an immune response of helper T-cell infiltrates occurs, surrounding the Demodex antigens in patients with rosacea (Forton 2012). Other causes of rosacea that are being investigated include dermal matrix degeneration, pilosebaceous unit abnormalities, ferritin expression, reactive oxygen species, and dysfunction of antimicrobial peptides (Crawford et al. 2004).