According to the National Institute of Diabetes and Digestive and Kidney Disorders (NIDDK), the thyroid gland makes two hormones (triiodothyronine and thyroxine) that affect the amount of moisture in the skin.

Cold sores are common and often appear on the lips. A version of herpes simplex type 1, these sores look like small little blisters that crack and split or even bleed. The virus stays dormant in your body until you get ill, undergo stress or experience hormonal changes.

Your calf muscle is located on the back of your lower leg. Calf muscles can become strained or pulled due to excessive physical activity, overuse or a direct blow to the leg. Stretching before exercise often helps to prevent sore calf muscles.

If people stand back when you remove your shoes, there’s an obvious problem. Both embarrassing and unsanitary, shoe odor can make for an uncomfortable situation. Not only do your shoes smell bad -- it’s safe to assume that your socks and feet smell the same way.

Human papillomavirus, or HPV, is the primary pathogen that causes common warts to manifest on the hands, feet and sex organs of both men and women. HPV can be transmitted through sexual contact and some varieties have been linked to cervical cancer in women.

Just like a rubber band, your skin is designed to stretch and snap back — when the skin stretches too far, it breaks instead of snapping back. This results in scar tissue development known as stretch marks. These red-and purple-markings can be the unsightly reminder of weight gain and/or a growth spurt.

Cold sores are infectious clusters of fluid-filled lesions that are caused by the herpes simplex virus 1, according to the Mayo Clinic. If you’ve had cold sores, you may notice a cold sore forming a couple of days before you can see it.

Skin blisters typically appear as circular, raised areas of fluid that collect underneath the top layer of your skin. The fluid, called serum, is usually clear to yellow in color and comes from your damaged blood vessels. Blisters develop to protect damaged skin from further harm.

Both melanoma and age spots can cause brown lesions on the skin. It is very important to differentiate these two skin conditions. While age spots can be a cosmetic nuisance, they are harmless. Melanoma, however, can be deadly. In fact, melanoma is the most dangerous form of skin cancer.

It is perfectly normal for infants to lose their hair during the first few months of life. The growth cycles of the hair during this age goes through fluctuations and can lead to hair loss.

A rash, also called dermatitis, can cause small red bumps to develop on the chest. Some rashes may just be an embarrassing annoyance, while others, especially when combined with additional symptoms such as a fever, can be the sign of a serious condition.

Chemical burns occur when skin comes into contact with chemicals resulting in irritation, bumps or blisters. Longer exposure to chemicals can cause a reaction in the body. First aid is the first line of defense in treating minor chemical burns. There are home remedies that can minimize the damage and treat the burns.