Chapter 118: Acne Vulgaris

PATIENT STORY

A 16-year-old boy (Figure 118-1) with severe nodulocystic acne and scarring presents for treatment. After trying oral antibiotics, topical retinoids, and topical benzoyl peroxide with no significant benefit, the patient and his mother requested isotretinoin (Accutane). After 4 months of isotretinoin, the nodules and cysts cleared, and only a few papules remained (Figure 118-2). He is much happier and more confident with his appearance. His skin cleared fully after 6 months of isotretinoin.

INTRODUCTION

Acne is an obstructive and inflammatory disease of the pilosebaceous unit predominantly found on the face, but it may also involve the trunk. It can occur at any age, but it is most common during adolescence.

EPIDEMIOLOGY

Acne vulgaris affects more than 80% of teenagers and persists beyond the age of 25 in 3% of men and 12% of women.¹ Neonatal acne is most often benign cephalic pustulosis. It is temporary and thought to be related to Malassezia species (Figure 118-3) (see Chapter 114, Normal Skin Changes).

ETIOLOGY AND PATHOPHYSIOLOGY

The four most important steps in acne pathogenesis are:

1. Sebum overproduction related to androgenic hormones and genetics

2. Abnormal desquamation of the follicular epithelium (keratin plugging)

3. Propionibacterium acnes proliferation

4. Follicular obstruction, which can lead to inflammation and follicular disruption

Acne can be precipitated by mechanical pressure such as a helmet strap (Figure 118-4) and medications such as phenytoin and lithium (Figure 118-5).

Some studies suggest that consumption of large quantities of milk (especially skim milk) and ...