There are many myths around the factors that influence acne that should be dispelled. These include:
- acne is caused by poor hygiene
- only teenagers get acne
- popping pimples makes them go away faster
- acne scarring can be easily fixed
- acne always goes away on its own – it may eventually burn out after days, weeks, months, or years but, unfortunately, the longer a patient has acne, the greater the risk for permanent scarring.
Diet is a controversial triggering factor, with the common misconception that an unhealthy diet is always the cause of acne in every person. Recent evidence suggests that in a select group of patients, high sugar intake, high dairy intake and a high glycaemic index diet may contribute to the development of acne, thought to be mediated by mammalian target of rapamycin complex 1 (mTORC1) signalling (Figure 1).17
It is important to set realistic expectations for treatment success and to offer patients a review to see if management needs to be altered.
The physical examination
Acne severity can be quickly assessed by looking at the patient’s face and torso. There is no standard method of acne grading, it can be simply classified as:
- mild – noninflammatory or inflammatory comedones (blackheads or whiteheads; Figure 2a)
- moderate – with inflammatory papules and pustules (Figure 2b)
- severe – with deeper inflammatory nodules and cysts (Figure 2c).
Many patients, especially those with darker skin (Fitzpatrick III or higher), may have postinflammatory redness or hyperpigmentation as inflammatory lesions resolve, which are often mistaken as active acne lesions or scarring.
Patients with severe acne with deep nodules and cysts that has not responded to treatment, and those with uncommon forms of acne such as acne conglobata and acne fulminans, may require urgent referral to a dermatologist for prescription of oral or intralesional corticosteroids or oral isotretinoin. Patients who have a psychological impact may require counselling with a psychologist or psychiatrist as well as referral for consideration of oral isotretinoin therapy.
Acne in adults can look the same as teenage acne. Both rosacea and perioral dermatitis can occur at the same time as adult acne but the clinical hallmark of acne is the comedone.
Most patients with acne do not need laboratory investigations. Consider hormonal acne in patients who have symptoms of hyperandrogenism in the context of polycystic ovary syndrome; a hormonal assay should be performed in the luteal phase of the menstrual cycle after the patient has stopped taking the oral contraceptive pill for at least one month. Tests for women with suspected hormonal acne include measurement of serum dehydroepiandrosterone sulfate, total testosterone, free testosterone and sex hormone binding globulin levels and the luteinising hormone/follicle stimulating hormone ratio.8 Patients with hormonal acne who are also insulin resistant may be at risk of developing diabetes and cardiovascular disease later in life.
If patients are having baseline investigations for oral isotretinoin, it may be helpful to order the following tests: liver function tests, creatine kinase (in athletic patients) and fasting lipids. Beta human chorionic gonadotropin should be added as a pregnancy screen in female patients. In healthy individuals, less frequent ongoing monitoring may be safe for those who are receiving typical doses of isotretinoin.18