A GP can diagnose acne by looking at your skin. This involves examining your face, chest or back for the different types of spot, such as blackheads or sore, red nodules.

How severe your acne is will determine where you should go for treatment and what treatment you should have.

The severity of acne is often categorised as:

• mild – mostly whiteheads and blackheads, with a few papules and pustules
• moderate – more widespread whiteheads and blackheads, with many papules and pustules
• severe – lots of large, painful papules, pustules, nodules or cysts; you might also have some scarring

For mild acne, you should speak to a pharmacist for advice. For moderate or severe acne, speak to a GP.

If acne suddenly starts in adult women, it can be a sign of a hormonal imbalance, especially if it's accompanied by other symptoms such as:

• excessive body hair (hirsutism)
• irregular or light periods

The most common cause of hormonal imbalances in women is polycystic ovary syndrome (PCOS).

PCOS can be diagnosed using a combination of ultrasound scans and blood tests.

Read more about diagnosing PCOS.