Why: Some medications may exacerbate acne e.g. lithium, phenytoin, topical and systemic corticosteroids, quinine, oral contraceptives

Why: Different patterns of acne can reflect differing underlying processes. For example acne rosacea occurs almost only on the face, whereas acne vulgaris can occur on the face, neck, chest and back.

Why: Different patterns of acne can reflect differing underlying processes. For example acne rosacea occurs almost only on the face, whereas acne vulgaris can occur on the face, neck, chest and back.

Why: Acne which has only recently begun in an adolescent may simply be a part of puberty and the hormonal changeswhich occur at that time. Acne which continues however past adolescence (particularly in women) may be the result of a less innocuous cause such as hirsutism.

Why: Some types of acne such as acne rosacea can be triggered by consuming alcohol or particular (usually spicy) foods. Alternatively, other types of acne (acne vulgaris) may appear to be triggered by insufficient or ineffective cleansing of the affected skin thus allowing skin secretions such as sebum to accumulate.

Why: Some oral contraceptives can increase acne, whilst others can decrease it.

Why: In women of reproductive age there can be times in their menstrual cycle when they may be more prone to acne, particularly in the premenstrual period.

Why: Polycystic ovary syndrome can cause hormonal imbalances which result in acne outbreak.