Your dermatologist is always the best source of guidance for hard-to-treat cases of acne. If you are having trouble making up your mind whether you need to see a dermatologist, here are five situations in which a doctor’s care is required.

1. Your skin has been clear, or mostly clear, and you have suddenly broken out in pimples

Acne usually develops slowly. If you have a sudden breakout of severe acne, especially if it is not limited to the face, a simple skin infection is likely not to be the real problem. Only your dermatologist can tell you for sure, but sudden and severe outbreaks of pimples can be symptoms of an acute hormone imbalance, a serious complication of hormone replacement therapy (with either estrogen or testosterone), or even the very first symptoms of potentially crippling conditions such as acne fulminans or psoriatic acne. Joint pain with an acne breakout is a signal that medical attention is urgently needed.

2. You develop cysts

An acne cyst is basically a pimple covered by healthy skin. Cystic acne is most likely to strike in the early 20’s, and it is most common in people who had little or no acne in their teens. As long as the skin is growing rapidly, pores stay open, but when the skin reaches maturity, cysts can form. Never try to lance or needle cystic acne on your own. You will probably fail to remove the infection but you are likely to create a nasty scar.

3. Your acne clears up but leaves skin spots behind

Many people who have deep, golden skin tones have more problems with the spots left behind by acne than they do with acne itself. The skin fights inflammation with the antioxidant pigment melanin. After acne clears up, melanin is left behind. Melanin deposits are especially visible on Asian skin, but people of Asian heritage often have unwanted reactions to skin lighteners. In some Asian skin types, the skin lightening agent hydroquinone, which usually works well on European skin types, can actually dye the skin purple. Your dermatologist can prevent skin-lightening disasters caused by choosing the wrong products.

4. You have deep brown or black pigments in your skin, and you develop nasty pimples where you have ingrown hairs

On some skin types, a bump or a pimple that pops up over an ingrown hair or whisker is not caused by infection. It is more likely to be an autoimmune reaction that can cause permanent damage to the skin. Your dermatologist can give you the treatment you really need to get these kinds of blemishes under control.

5. You need treatment for a “pimple emergency” just before an important date, social event, or photo shoot

Your dermatologist can deflate pimples safely, usually with a hydrocortisone injection. Don’t try this at home, because repeated injections of steroids into the same site can cause permanent loss of pigmentation in the skin.

Your doctor is also your best source of reliable information about the best new acne treatments. Seeing the dermatologist may be expensive in the short run, but your doctor can help you avoid the long-lasting skin problems that uncontrolled acne can bring.