Both SLE and rosacea may be exacerbated by sun exposure, and patients may report burning and stinging.16-18 Performing a complete physical examination, performing a skin biopsy with hematoxylin and eosin and direct immunofluorescence, and checking serologies including antinuclear antibody (ANA) can assist in making the diagnosis. It is important to note that elevated ANA, albeit lower than what is typically seen in SLE, has been reported in rosacea patients.19 If ANA is elevated, more specific SLE antibodies should be tested (eg, double-stranded DNA). Additionally, SLE can be differentiated on histology by a considerably lower CD4:CD8 ratio, fewer CD4+CD25+ regulatory T cells, and more CD123+ plasmacytoid dendritic cells compared to rosacea.20
Seborrheic Dermatitis
Seborrheic dermatitis is a frequent cause of facial erythema linked to the Malassezia yeast species in susceptible individuals. Seborrheic dermatitis has a notable prevalence in women of African descent and often is considered normal by these patients.21 Rosacea and seborrheic dermatitis are relatively common dermatoses and therefore can present concurrently. In both diseases, facial erythema may be difficult to discern upon cursory inspection. Seborrheic dermatitis may be distinguished from rosacea by the clinical appearance of erythematous patches and plaques involving the scalp, anterior and posterior hairlines, preauricular and postauricular areas, and medial eyebrows. Both seborrheic dermatitis and rosacea may involve the nasolabial folds, but the presence of scale in seborrheic dermatitis is a distinguishing feature. Scale may vary in appearance from thick, greasy, and yellowish to fine, thin, and whitish.22 In contrast to rosacea, the erythematous lesions of seborrheic dermatitis often are annular in configuration. Furthermore, postinflammatory hypopigmentation and, to a lesser extent, postinflammatory hyperpigmentation are key clinical components of seborrheic dermatitis in SOC patients but are not as commonly observed in rosacea.
Dermatomyositis
Dermatomyositis is a systemic autoimmune disease characterized by progressive and symmetric proximal musculoskeletal weakness and cutaneous findings. Facial erythema in the malar and nasolabial folds can be seen in patients with dermatomyositis18; however, the facial erythema seen in dermatomyositis, known as heliotrope rash, has a violaceous dusky quality and also involves the periorbital region. The violaceous hue and periorbital involvement are distinguishing features from rosacea. Okiyama et al23 described facial macular violaceous erythema with scale and edema in Japanese patients with dermatomyositis on the nasolabial folds, eyebrows, chin, cheeks, and ears; they also described mild atrophy with telangiectasia. Other clinical signs to help distinguish rosacea from dermatomyositis are the presence of edema of the face and extremities, Gottron papules, and poikiloderma. Dermatomyositis is a disease that affects all races; however, it is 4 times more common in black vs white patients,24 making it even more important to be able to distinguish between these conditions.
Acne Vulgaris
Acne vulgaris, the most commonly diagnosed dermatosis in patients with SOC, is characterized by papules, pustules, cysts, nodules, open and closed comedones, and hyperpigmented macules on the face, chest, and back.25,26 The absence of comedonal lesions and the presence of hyperpigmented macules distinguishes acne vulgaris from rosacea in this population.1 In addition, the absence of telangiectasia and flushing are important distinguishing factors when making the diagnosis of acne vulgaris.
Sarcoidosis
Sarcoidosis is a multisystem inflammatory disease characterized histologically by the presence of noncaseating granulomas in sites such as the lungs, lymph nodes, eyes, nervous system, liver, spleen, heart, and skin.27 Cutaneous sarcoidosis is known as a great mimicker of many other dermatoses, as it may present with multiple morphologic features. Cutaneous sarcoidosis most typically presents as papules, but nodules, plaques, lupus pernio, subcutaneous infiltrates, and infiltration of scars also have been identified.28 Sarcoid papules typically are 1 to 5 mm in size on the face, neck, and periorbital skin29; they are initially orange or yellow-brown in color, turn brownish red or violaceous, then involute to form faint macules.30 Papular lesions may either resolve or evolve into plaques, particularly on the extremities, face, scalp, back, and buttocks. Additionally, there are a few case reports of patients with cutaneous sarcoidosis presenting with large bulbous nasal masses initially thought to be rhinophyma.31-33 Finally, it may be difficult to distinguish sarcoidosis from granulomatous rosacea, which is characterized by firm yellow, brown, violaceous, red, or flesh-colored monomorphic papules or nodules affecting the perioral, periocular, medial, and/or lateral areas of the face (Figure 2).4,34 Patients also can have unilateral disease.35 Patients with granulomatous rosacea lack flushing and erythema as seen in more characteristic presentations of rosacea. They may report pain, pruritus, or burning, or they may be asymptomatic.36 Features that distinguish granulomatous rosacea from sarcoidosis include the absence of nodules, plaques, lupus pernio, subcutaneous infiltrates, and infiltration of scars. Clinical, histological, and radiographic evaluation are necessary to make the diagnosis of sarcoidosis over rosacea.
Figure 2. Granulomatous rosacea in a woman with Fitzpatrick skin type VI. Photograph courtesy of Susan C. Taylor, MD (Philadelphia, Pennsylvania).
Steroid Dermatitis
Steroid dermatitis involving the face may mimic rosacea. It is caused by the application of a potent corticosteroid to the facial skin for a prolonged period of time. In a report from a teaching hospital in Baghdad, the duration of application was 0.25 to 10 years on average.37 Reported characteristics of steroid dermatitis included facial erythema, telangiectasia, papules, pustules, and warmth to the touch. Distinguishing features from rosacea may be the presence of steroid dermatitis on the entire face, whereas rosacea tends to occur on the center of the face. Diagnosis of steroid dermatitis is made based on a history of chronic topical steroid use with rebound flares upon discontinuation of steroid.
Final Thoughts
Rosacea has features common to many other facial dermatoses, making the diagnosis challenging, particularly in patients with SOC. This difficulty in diagnosis may contribute to an underestimation of the prevalence of this disease in SOC patients. An understanding of rosacea, its nuances in clinical appearance, and its mimickers in SOC patients is important in making an accurate diagnosis.