Theresa A. Bedford Acne vulgaris is the most common dermatologic disorder in the United States. Although first observed in the pediatric age group, the condition can persist well into the adult years. Whereas it is not usually a serious medical problem, acne should never be dismissed as a minor condition that will eventually be outgrown. The psychological effects of prolonged acne and scars include poor confidence, impaired social contact, embarrassment, shame, anxiety, and difficulty with employment.1 Advances in acne treatment enable management of this disease for many patients. Acne vulgaris is a disorder of the pilosebaceous follicles resulting in increased sebum production, altered keratinization, inflammation, and bacterial colonization. Acne is characterized by the formation of comedones, erythematous papules and pustules, and nodules.1 Up to 80% of individuals with a first-degree relative with acne may have acne.2 Acne affects nearly all people 15 to 17 years of age.2,3 Up to 85% of people aged 12 to 24 have acne. Severity has been correlated to pubertal maturity. Of adults in their 20s and 30s, respectively, up to 64% and 43% of individuals have acne. Women beyond the age of 25 tend to have acne related to circulating androgens.2 Although acne is not clearly associated with ethnicity, black individuals are more prone to postinflammatory hyperpigmentation.3 There are four key processes in the development of acne: inflammation (inflammatory mediators are released into the skin); abnormal desquamation of keratinocytes, which plugs the pilosebaceous follicles; increased or altered sebum production; and colonization with Propionibacterium acnes.2,4 Before and during puberty, hormonal stimulation increases production of the sebaceous glands in the pilosebaceous follicles. Abnormally adherent keratinocytes cause plugging of the pilosebaceous follicles, which contributes to the formation of the primary lesion (the comedone). The open comedone (blackhead) is an obstruction at the follicular mouth, which is filled with a plug of stratum corneum cells. The black color is a result of compacted follicular cells, not dirt.5 Closed comedones (whiteheads) are a result of cystic swelling of the follicular duct below the epidermis. These closed comedones are the precursors of inflammatory papules and pustules (Fig. 42-1). Inflammation, increased sebum production, altered keratinization, and bacterial colonization with P. acnes lead to production of chemotactic factors and proinflammatory cytokines.3 Inflammatory material around the comedone creates inflammatory papules and pustules. Self-inflicted trauma such as scratching and squeezing of the lesions may result in scars, appearing as pits or hypopigmented spots. Furthermore, the rupture of cystic acne lesions may also result in scar formation without any manipulation of the lesions. Another potential aftereffect of acne is the formation of keloids, especially over the sternum and upper back. In patients with darker skin, inflammatory lesions often resolve with postinflammatory hyperpigmentation. Patients can be reassured that this “staining” is not scarring and usually clears spontaneously after several months.3,4,6 The duration of acne, past treatments, use of topical products for acne, menstrual history and contraceptive method, family history of acne, allergies, past medical history and review of systems, and current medications should be included in the patient’s history. It is important to document how long previous treatments were used and any side effects. One frustrating fact of acne therapy is that most treatments require 6 to 12 weeks to take effect; shorter treatment therapies may not have been given an adequate trial.4 While obtaining the history, the provider must consider that seasonal and hormonal factors may affect acne flares. More severe lesions occur during the winter months when there is less sunlight because acne is an inflammatory condition that improves with exposure to ultraviolet light.7 A careful history should include an inquiry about exposure to cosmetic and hair styling products. Cosmetic acne can result from oil-based cosmetics, lotions, and hair products. It is usually worse in the areas in contact with the cosmetic. Pomade acne is seen on the forehead and neck as the result of oily lotions and creams used to style the hair.2,4 Mechanical acne can result from friction from headbands, hats, helmets, chin straps, collars, and tight bras. This presentation typically demonstrates acneiform lesions in the area where these devices contact the body, whereas other locations are spared. Acne excoriée is a subtype of acne in which the primary lesions have been scratched. Patients with acne excoriée must be encouraged to stop manipulating or scratching these lesions as an important part of successful therapy for this acne condition.8 Certain medications can induce or aggravate acne (Box 42-1).9 Typically, drug-induced acne has a rapid onset and may involve the usual acne areas as well as unusual areas, such as the postauricular area, upper arms, lower back, abdomen, and legs.8 Lifestyle factors may play a role in acne exacerbations. Although diet has not been shown to cause acne, diets with high glycemic loads and dairy have been associated with an increase in acne exacerbations.10 In addition, stress has been to be a major trigger for exacerbations. Although smoking and poor hygiene have not been shown to cause or worsen acne, clinicians are encouraged to promote a healthy lifestyle for their patients.3 A physical examination should include the type, location, and extent of acne lesions.4 The highest concentration of sebaceous glands occurs on the face, chest, back, and shoulders. Patients may be seen with a variety of lesions, including comedones, papules, pustules, and nodules. Surprisingly, the skin of a patient with acne will not necessarily be oily.2 Mild acne covers less than a fourth of the face without the presence of nodules or scarring. Moderate acne involves half of the face with some nodules and few scars. Severe acne involves at least three quarters of the face with multiple nodules and scars.4 Acne is diagnosed by physical examination. Laboratory blood testing is necessary only if adrenal or gonadal dysfunction is a possible cause.4 Other conditions may be misdiagnosed as acne. These include milia, rosacea (Fig. 42-2), the adenoma sebaceum lesions of tuberous sclerosis, nevus comedonicus, miliaria of the newborn, flat warts, and molluscum contagiosum.
Acne Vulgaris
Definition and Epidemiology
Pathophysiology
Clinical Presentation and Physical Examination
Diagnostics and Differential Diagnosis
Acne Vulgaris
Chapter 42
