A common myth is that rosacea is an adult form of acne. In fact, rosacea is a chronic inflammatory condition of unknown origin characterized by flushing, redness, papules, pustules and spidery surface veins. Unlike acne that can affect the face, chest, back and shoulders, rosacea rarely affects the skin other than the face.

Acne is caused by excess sebum (the oily substance produced by the sebaceous glands) and the bacteria found on the skin, P. acnes. While normally skin cells and sebum are shed from the pores, in acne, this debris causes a plug, called a comedone. Comedones can be open (blackhead) or closed (whitehead).

P. acnes and overproduction of sebum do not play a role in rosacea. While the exact cause of rosacea is not known, evidence suggests it may be due to the degeneration of collagen and elastin, leading to the dilation of small blood vessels. There is also speculation that mites or staphylococcal bacteria may play a role.

Both acne and rosacea can cause pustules (a raised, pus-filled blemish) and papules (a solid, raised blemish), but only acne has the blackheads and whiteheads. Rosacea is also triggered by external factors, such as hot or cold weather, spicy foods, hot drinks and alcohol. Think you may have rosacea? Try the Rosacea Checklist.

If you have some of the symptoms mentioned above, consult your doctor or a dermatologist, a doctor who specializes in skin conditions. Both acne and rosacea can cause scarring if not treated. If you don't have a dermatologist, you can find one near you by using the DermFinder.