Introduction

Acne is an easily treated cause of disfigurement and psychological morbidity. It affects more than 80% of people at some point in their life,1 up to 14% of whom consult their general practitioner (GP) and 0.3% a dermatologist. About 3.5 million consultations with GPs occur in the United Kingdom annually for acne.^w1 Morbidity can be high and associated with disfigurement, pain, loss of confidence, and impairment of normal social and workplace function, with documented effects on quality of life including depression, dysmorphobia, and even suicide.^{w2 w3}

What are the clinical features of acne?

In most cases it is not difficult to diagnose acne. It comprises a combination of papules, pustules, blackheads and whiteheads (open and closed comedones), nodules, and scarring. Background redness and greasy skin, known as seborrhoea, usually occur. It is important to avoid confusion with other conditions such as acne rosacea (box 1). Treatment with systemic corticosteroids can cause steroid induced acne, and the use of anabolic steroids can cause “bodybuilders acne.” Potent topical steroid treatment can cause perioral or periorbital dermatitis with papules and pustules. Pustular drug eruptions and bacterial and fungal folliculitis can also resemble acne but can be distinguished by the absence of comedones.

Typically, acne persists over years. Nodules can be more painful, more unsightly, and carry a greater risk of scarring than more superficial disease. In acne conglobata, nodules are widespread with interconnecting channels containing haemorrhagic, purulent exudate. When this evolves rapidly with fever, arthritis, and neutrophilia it is called acne fulminans.

Postinflammatory pigmentation can last months and occasionally years, especially in patients with dark skin. The upper chest and shoulders may develop hypertrophic or keloid scarring for 12 months or more. Atrophic or “ice pick” scars are typically found on the face. Small depressions and mild discoloration may last for six to 12 months, but usually …