PATHOGENESIS
Rosacea (sometimes called acne rosacea) is a chronic dermatological disease that can affect both the skin and the eyes. It has no proven cause, but bacteria associated with Demodex mites have been implicated. The condition may be related to the overexpression of cathelicidin. Cathelicidins, cationic peptides with antimicrobial activity, contribute to neutrophil recruitment, angiogenesis, and cytokine release, which may play a role in the inflammatory skin changes seen in patients with rosacea. Rosacea is associated with cutaneous sebaceous gland dysfunction of the face, neck, and shoulders. Although rosacea has generally been thought to be more common in fair-skinned individuals, it may simply be more difficult to diagnose in patients with dark skin. It is important to look for the sometimes subtle clinical findings by external examination in a brightly lit room. Although alcohol consumption can contribute to a worsening of this disorder because of its effect on vasomotor stability, most patients with rosacea do not have a history of excessive alcohol intake. In some patients, exacerbation can be triggered by emotional stress, ingestion of hot or spicy foods, or a hot or cold environment.
CLINICAL PRESENTATION
Rosacea frequently involves the eyes. It affects individuals aged 30–60 years most commonly and women slightly more often than men, although ocular rosacea can occur in young patients and is often underdiagnosed. Rosacea is characterized by excessive sebum secretion with frequently recalcitrant chronic blepharitis. Eyelid margin telangiectasia is very common, and the often-associated meibomian gland distortion, disruption, and dysfunction can lead to recurrent chalazia. The ocular condition can progress, leading to chronic conjunctivitis, severe stromal keratitis (Fig 3-14), marginal keratitis (Fig 3-15A), sterile ulceration, episcleritis, or iridocyclitis. If properly treated, these lesions can resolve with few sequelae. Repeated bouts of ocular surface inflammation can cause corneal neovascularization and scarring (Fig 3-15B).
Facial lesions consist of telangiectasias, recurrent papules and pustules, and midfacial erythema (Fig 3-16). Rosacea is characterized by a malar rash with unpredictable flushing episodes. Rhinophyma, thickening of the skin and connective tissue of the nose, is a characteristic and obvious sign associated with this disorder, but such hypertrophic cutaneous changes occur relatively late in the disease process.
MANAGEMENT
The ocular and systemic diseases are managed simultaneously, and oral tetracyclines are the mainstay of therapy. Tetracyclines have anti-inflammatory properties that include suppression of leukocyte migration, reduced production of nitric oxide and reactive oxygen species, inhibition of matrix metalloproteinases, and inhibition of phospholipase A2. In addition, tetracyclines may reduce irritative free fatty acids and diglycerides by suppressing bacterial lipases. Erythromycin or azithromycin may be used when tetracyclines are not appropriate. Oral azithromycin should not be used in patients prone to cardiac arrhythmia.
With time, oral therapy with doxycycline or minocycline can be tapered. In addition to oral therapy, topical therapy with metronidazole gel 0.75%, metronidazole cream 1%, or azelaic acid gel 15% applied to the affected facial areas can significantly reduce facial erythema. Azelaic acid 15%, the only gel approved by the FDA for the treatment of papulopustular rosacea, is thought to suppress rosacea through anti-inflammatory and antimicrobial mechanisms.
Ulcerative keratitis in rosacea can be associated with infection or due to a sterile inflammatory response. Once it is ascertained that ulceration is noninfectious, topical corticosteroids, used judiciously, can play a significant role in reducing sterile inflammation and enhancing epithelialization of the cornea. In advanced cases with scarring and neovascularization, conservative therapy is generally recommended. Penetrating keratoplasty is a high-risk procedure in the rosacea patient, and the prognosis may be poor, particularly if the ocular surface is severely compromised.
Intense pulsed-light therapy may help reduce eyelid erythema as well as symptoms related to meibomian gland dysfunction. See “Medical management of evaporative dry eye,” earlier in the chapter.
National Rosacea Society website. Available at www.rosacea.org. Accessed February 3, 2017.
Schittek B, Paulmann M, Senyürek I, Steffen H. The role of antimicrobial peptides in human skin and in skin infectious diseases. Infect Disord Drug Targets. 2008;8(3):135–143.
Excerpted from BCSC 2020-2021 series: Section 10 - Glaucoma. For more information and to purchase the entire series, please visit https://www.aao.org/bcsc.