Acne is easily diagnosed by physical examination and medical history.

When signs of of androgen excess are present such as menstrual irregularity, hair loss on the scalp and hair growth on the body, specialist referral is essential to exclude overproduction of androgenic hormones by the ovaries or adrenal glands.

The diagnosis of acne is usually straightforward, but acne-like lesions may be caused by systemic medication (eg. cortisone), cortisone applied to the face, and, greasy cosmetics.

Rosacea is a seperate condition and characterised by redness, red bumps and pimples. Comedones are absent. Patients are usually middle aged.