Who is susceptible: Kauvar says spider and varicose veins are usually inherited (thanks mom!) and more than half of women get them. They can be triggered by pregnancy and hormones, or by standing for long periods of time.

How to prevent them: Keep your calf muscles toned, Kauvar says, because it helps send the blood in your legs back up to your heart. You can also try wearing compression hose if your legs hurt from standing.

How to treat them: "Sclerotherapy (injecting a chemical solution into the vein with a hair thin needle) is the main treatment, but lasers are used in specific circumstances," Kauvar says. If they are causing you pain (or you just want to get rid of them), talk to your doctor.

At-home treatments: While Kauvar says that in-office procedures work best, you can get results with topical products at home. Look for products with retinoids and/or vitamin C to stimulate collagen, which will help tighten the skin and minimize the look of depressed acne scars. (Try: SkinCeuticals Retinol 1.0, $48 or Dermalogica ChromaWhite TRx System, $188.)

In-office treatments: Kauvar says you can use resurfacing lasers to cause new collagen growth (which will fill in the depressions of the scars). Another option is "subcision, where a needle is inserted beneath the skin to break up the scar tissue," Kauvar says. "Often multiple different approaches are needed for best results."

What causes it: Teuschler lays out a laundry list of breakage causes: chemical treatments and over-processing your hair (like too much coloring, bleaching or perming), too much combing or brushing, too much heat styling (blow drying, flat ironing or curling), too much sun or even scratching your scalp too much.

How to fix it: Aside from the obvious, which is to minimize all the factors above, look for products that contain silicones, like dimethicone, to coat the hair and make it less prone to tangling (and getting broken when you brush your hair). Try not to brush hair when it's wet, instead use a leave-in conditioner to combat tangles (try: Marco Pelusi Anti-Frizz Leave-In Conditioner, $35 or TreSemme Detangle Leave-In Spray, $4.73). You can also do weekly deep conditioning treatments to help add moisture back to your hair (try Pantene Relaxed & Natural Breakage Defense Deep Conditioning Mask, $5.99). Teuschler adds that if your breakage is coming from scratching your scalp, use an anti-dandruff shampoo with pyrithione zinc to stop the itching.

What it is: "Melasma is known as 'the mask of pregnancy' and can occur in pregnancy, with birth control pills or with no additional hormones beyond those of being a woman," Waldrof says. It typically looks like mottled brown discoloration on your cheeks, forehead or upper lip. It's triggered by UV exposure.

How to treat it: Topical retinoids and hydroquinone can help lighten the areas, Waldorf says. You can also try microdermabrasion or light peels, or if that doesn't work, a dermatologist may recommend the fraxel laser. The most important thing for melasma sufferers is to be "vigilant with sun protection," Waldorf says, because it usually recurs with sun exposure.

What it is: "Psoriasis is a skin disorder characterized by red scaly plaques classically on the elbows and knees but also elsewhere on the body," Waldorf says.

How to treat it: For mild cases, topical moisturizers or steroids will usually work, but for more extreme cases, your dermatologist will need to prescribe a biologic drug, Waldorf says. Unfortunately, psoriasis can't be prevented.