Melanin is what makes up your natural skin tone. Produced by cells called melanocytes, melanin also provides you with natural hair color. When melanin production slows, your hair and skin lighten, which sometimes forms a condition known as vitiligo.

Hives occur when specialized immune system cells in the skin, called mast cells, activate. Activated mast cells release inflammatory chemicals, including histamine and others. This causes dilation of nearby blood vessels and leakage of fluid into the superficial skin layer, resulting in hives.

Keloids are believed to be caused by a hereditary condition. This condition causes scar tissue to over grow after damage to the skin. These lumps on the skin are made of collagen and are not communicable to others. Keloids may be slightly painful and itchy but other than that they rarely cause any other symptoms.

Some signs that a man has a penile yeast infection and needs a prompt visit to the doctor include, but are not limited to, constipation, bad breath, bloating, indigestion, frequent intestinal gas, frequent diarrhea, very loose stools, sexual dysfunction, irritability, mood swings, fatigue or lack of energy, memory loss

Fish oil is a rich source of omega-3 fatty acids that may help with certain medical conditions. While you can get omega-3 fatty acids by eating fish, you can also buy fish oil as a supplement. As with any supplement, if you have any known allergies, you are at risk of developing allergic reaction.

Many people who suffer from varicose veins cover them up by making pants and long skirts permanent fixtures in their wardrobes. While there’s no arguing that ropey, blue leg veins are no fun to deal with, there are other ways to cover them up without wearing head-to-toe clothing.

Your hair is constantly going through phases of growth and loss. In fact, most people lose on average between 50 and 100 hairs every day, according to the American Academy of Dermatology.

Hypoallergenic soaps, lotions and pillows are a necessity for allergy sufferers. Even hypoallergenic eyeglass frames are available on the market. Contact dermatitis -- or irritation of the skin -- is a common problem for eyeglass wearers.

Achy legs after taking part in heavy exercise isn't much of a surprise, especially if you're not used to that level of physical activity. If your legs continually ache and feel heavy, however, you could have varicose veins.

Shingles, also known as herpes zoster, is caused by the chickenpox virus. If you’ve ever had chickenpox, you can develop shingles because the virus remains in your body. It can be dormant for many years and then unexpectedly become active again and cause shingles.

Infections and allergic reactions can cause a raised, pimple-like rash that's unrelated to acne. Any time you see unexplained changes on your skin or experience a rash that continues getting worse, see a doctor.

A common reason for men to come into a dermatology clinic is to treat an itchy rash in the groin area. In many instances the cause is jock itch (although most of the patients who have it are clearly not jocks). Jock itch is a fungus infection of the groin that occurs mostly in men.