29
Acne Vulgaris
• A tendency to develop moderate to severe acne can run in families.
• Multiple factors affecting the pilosebaceous unit contribute to acne pathogenesis (Fig. 29.1), a process that typically begins when androgen production increases at adrenarche.
Clinical Features and Variants of Acne
• Favors the face and upper trunk, sites with well-developed sebaceous glands.
– Closed comedones (whiteheads) are small (~1 mm), skin-colored papules without an obvious follicular opening (Fig. 29.2A,B).
Fig. 29.2 Comedonal acne vulgaris. A Closed comedones highlighted by side lighting. B Open and closed comedones as well as post-inflammatory hyperpigmentation on the cheek. C Prominent open comedones in a patient with scarring cystic acne. A, Courtesy, Ronald P. Rapini, MD; B, Courtesy, Andrew Zaenglein, MD, and Diane Thiboutot, MD.
– Open comedones (blackheads) have a dilated follicular opening filled with a keratin plug, which has a black color due to oxidized lipids and melanin (Fig. 29.2B,C).
– Erythematous papules and pustules (Fig. 29.3A).
Fig. 29.3 Inflammatory acne vulgaris. A Papules, obvious pustules, and atrophic scars are present. B Severe nodulocystic acne. This form is best treated with low doses of isotretinoin initially (± a preceding course of oral antibiotics) to avoid precipitating a flare. A, Courtesy, Andrew Zaenglein, MD, and Diane Thiboutot, MD.
– Nodules and cysts filled with pus or serosanguinous fluid; may coalesce and form sinus tracts (Fig. 29.3B).
– Acne conglobata (severe nodulocystic acne) is classified in the follicular occlusion tetrad along with dissecting cellulitis of the scalp, hidradenitis suppurativa, and pilonidal cysts (see Chapter 31); it is also a part of pyogenic arthritis, pyoderma gangrenosum, and acne conglobata (PAPA) and pyoderma gangrenosum, acne, and suppurative hidradenitis (PASH) syndromes.
• Inflammatory acne commonly results in post-inflammatory hyperpigmentation, especially in patients with darker skin, which fades slowly over time (Fig. 29.4A); nodulocystic acne (and less frequently other inflammatory > comedonal forms) often leads to pitted (Fig. 29.4B) or hypertrophic scars (the latter especially on the trunk; see Fig. 81.4).
Post-Adolescent Acne
Acne Excoriée
Acne Fulminans
• Favors boys 13 to 16 years of age.
• Coalescence into painful, oozing, friable plaques with hemorrhagic crusting, erosion/ulceration, and eventual scarring (Fig. 29.5).
Fig. 29.5 Acne fulminans. Inflamed, friable papulopustules and plaques with erosions, oozing, and formation of granulation tissue. Courtesy, Julie V. Schaffer, MD.
