Recognizing Rosacea: Tips on Differential Diagnosis

September 2019 | Volume 18 | Issue 9 | Original Article | 888 | Copyright © September 2019

Sandra Marchese Johnson MD FAAD,a Andrew Berg PA,b Chelsea Barr MPAS PA-Cc

ªJohnson Dermatology, Fort Smith, AR

BBerg Consulting and Investments, Inc, Lee’s Summit, MO

cHouston Skin Associates, Houston, TX

erythema, and papules and pustules (Figure 7); patients may report sensations of skin burning or pruritus. Dermoscopy may show portions of Demodex in and around the follicular opening. 21 Mites may also be seen on microscopy. Demodex mites are part of the normal skin flora but there is evidence of an increased density of Demodex mites in patients with rosacea.22 Patients with demodicidosis show a positive response to antidemodectic drugs.20

Gram negative folliculitis
Patients using prolonged courses of oral antibiotics for acne vulgaris or rosacea may develop gram-negative folliculitis, a persistent papulopustular rash (Figure 9). The antibiotic alters resident skin flora, allowing growth of gram-negative organisms in the nares, which can then spread to adjacent skin areas. Culture of the lesions yields gram-negative bacilli and rods (Escherichia coli, Klebsiella, Enterobacter, and Proteus species), and patients often report a sudden acne flare despite no change in treatment.19

Primarily Erythematous Presentation
Lupus erythematosus
Lupus erythematosus is an autoimmune disease with cutaneous manifestations that can resemble rosacea (Figure 10). Pustules are rare in the malar rash of lupus.23 Discoid lupus is named for the coin-like red, scaly lesions that appear on cheeks, nose, ears, and scalp. Lupus can also be associated with red scaly lesions that are similar to seborrheic dermatitis. In patients with skin of color, serologic testing, and skin biopsy may be warranted to correctly diagnose lupus.15 This is especially important if the patient is not responding to typical rosacea regimens.

Seborrheic dermatitis
Seborrheic dermatitis is common in males and often has onset at puberty. The clinical presentation includes symmetrical, well demarcated, yellowish red patches/plaques with overlying adherent, yellowish greasy scales in areas rich in sebaceous glands.24 Dermoscopic clues can be useful in distinguishing seborrheic dermatitis from rosacea. On dermoscopy, rosacea has linear vessels arranged in a polygonal network while seborrheic dermatitis has dotted vessels in a patchy distribution (Figure 8).21 Rosacea and seborrheic dermatitis often coexist in the same patient making the diagnosis even more difficult. The term dyssebacea is often used for patients suffering with multiple issues of the pilosebaceous unit including rosacea, seborrheic dermatitis, and sebaceous hyperplasia.

Photodamage typically includes rough skin, wrinkles/rhytids, as well as facial erythema and telangiectasia (Figure 12). Helfrich et al. argue that there is a subtype of photodamage characterized by significant telangiectasia and persistent facial erythema who lack other rosacea symptoms (flushing, burning, stinging). They note that this usually occurs in older men, and that a distinguishing clinical feature is localization of the telangiectasia and erythema more toward the lateral face rather than central face.25 Photodamage may also manifest as Favre-Racouchot Syndrome, a nodular cutaneous elastosis with cysts and multiple open and closed comedones that are often clustered in the periocular region.26