Acne and Rosacea

Acne

Acne vulgaris is one of the most common skin disorders in the general population, with an estimated 80% prevalence among adolescents. Acne is most common in younger patients, although adult-onset acne is not uncommon, particularly in women.

The pathogenesis of acne is multifactorial and includes the following steps:

• androgen-induced sebaceous hyperplasia

• abnormal keratinocyte proliferation leading to sebum accumulation within follicles

• increased proliferation of Propionibacterium acnes

• immune response (particularly activation of toll-like receptor 2) causing inflammation

Key risk factors for developing acne include the following:

• hormonal changes (e.g., puberty, polycystic ovary syndrome [PCOS], or exogenous androgens)

• family history

Clinical Manifestations

The pathognomonic cutaneous findings of acne are open and closed comedones (commonly referred to as blackheads and whiteheads, respectively). Additionally, acne is characterized by erythematous papules, pustules, and nodules distributed primarily on the face, chest, and upper back.

Severity of acne is classified as mild, moderate, moderately severe, or severe:

(Source: Acne. N Engl J Med 2005.)

Images of Acne

(Source: Acne. N Engl J Med 2005.)

(Source: Acne. N Engl J Med 2005.)

(Source: Acne. N Engl J Med 2005.)

(Source: Acne. N Engl J Med 2005.)

(Source: Therapy for Acne Vulgaris. N Engl J Med 1997.)

Treatment

Treatment of acne depends on the severity and involves a step-up regimen.

• Topical regimens for mild or moderate acne typically involve benzoyl peroxide, antibiotics, and retinoids. Clascoterone, a topical androgen antagonist, is a newer agent also approved for the treatment of acne.

• Oral agents can include antibiotics, androgen antagonists (e.g., spironolactone), oral contraceptive pills, or oral retinoids (e.g., isotretinoin).

• Only isotretinoin (13-cis retinoic acid) targets all four pathophysiologic factors of acne, and it is the only treatment that can result in remission of acne or significant reduction in severity. If an individual has severe acne or acne that is scarring and not responding to conventional therapies, isotretinoin should be considered. Some evidence suggests targeting a higher cumulative dose of isotretinoin to reduce the risk for relapse.

The following table summarizes the 2016 American Academy of Dermatology (AAD) guidelines for management of acne:

(Reference: Guidelines of Care for the Management of Acne Vulgaris. Am Acad Dermatol 2016.)

Rosacea

Rosacea is another common chronic inflammatory skin disorder that is most commonly seen in light-skinned individuals of Northern European ancestry but can be seen in individuals of all skin tones and ethnic descents. The pathogenesis is not completely known, but it is hypothesized to be due to inappropriate immune-system activation by exogenous triggers (e.g., ultraviolet radiation, exercise, alcohol, chocolate, Demodex mite proliferation). The subsequent inflammatory cascade leads to facial flushing and/or a sensation of heat or discomfort. Chronic rosacea can lead to lymphatic dysfunction and progress to various subtypes.

Clinical Manifestations

In contrast to patients with acne, patients with rosacea do not have comedones. Symptoms of rosacea are chronic with a history of flares. Frequently, patients will know the specific trigger.

Four subtypes of rosacea are clinically defined as follows:

(Source: Rosacea. N Engl J Med 2005.)

(Source: Rosacea. N Engl J Med 2005.)

(Source: Rosacea. N Engl J Med 2005.)

(Source: Ocular Rosacea. N Engl J Med 2016.)

The following table summarizes the classification, features, and treatment of rosacea:

(Source: Rosacea. N Engl J Med 2005.)

Treatment

Treatment of rosacea first involves avoidance of exacerbating factors. Additionally, therapy depends on rosacea subtype.

Nonpharmacologic management of rosacea is summarized in the following table:

(Source: Rosacea. N Engl J Med 2005.)

Additional interventions for rosacea include the following:

• For subtype 1 and subtype 2, the most common first-line therapies include topical metronidazole, ivermectin, or permethrin cream.

• Add-on therapy typically involves systemic antibiotics (most often doxycycline), although they can be started as first-line therapy at presentation for moderate-to-severe lesions.

• Laser therapy directed at blood vessels (e.g., pulsed dye laser) is an alternative with well-known efficacy.

• For rhinophymatous rosacea, surgical or ablative laser intervention is often necessary.

• Ocular rosacea necessitates the use of oral antibiotics.

Additional information about treatment of rosacea can be found here.