Did you know that your skin is your body’s largest organ? That is, in terms of weight between 6 and 9 pounds, and surface area, about 2 square meters. Your skin separates the inside of your body from the outside world. It protects you from bacteria and viruses and regulates the temperature of your body.

Conditions that irritate, clog, or burn your skin can cause symptoms such as redness, burning, swelling, and itching. Allergies, irritants, your genetic makeup and certain diseases and immune system problems can cause dermatitis, hives and other skin conditions. Many skin problems, such as acne, also affect your appearance. Your skin can also develop several types of cancers.

Here are the key facts about some of the most common skin problems:

Acne—A disease that affects the skin’s oil glands. The small holes in your skin. These acorns make a substance called sebum. The pores connect to the glands by a canal called a follicle. When the follicle of a skin gland clogs up, a pimple grows. Acne is the most common skin disease; An estimated 80 percent of all people have acne at some point. Early treatment is the best way to prevent scars. Your doctor may suggest over-the-counter (OTC) or prescription drugs.

Eczema—Also known as atopic dermatitis, it is a long-term skin disease. The most common symptoms are dry and itchy skin, rashes on the face, inside the elbows, behind the knees and on the hands and feet. At present, there is no single test to diagnose eczema, so doctors rely on information about you and your family.

Hives—Red and sometimes itchy on your skin. An allergic reaction to a drug or food usually causes them. People who have other allergies are more likely to have hives than other people. Other causes include infections and stress. Hives are very common. They usually go away, but if you have a serious case, you may need medical help.

Rashes (basic dermatitis)—Dry and itchy skin; Rashes on the face, inside the elbows, behind the knees, and on the hands and feet. Your doctor will help you develop a good skin care routine, learn to avoid things that cause breakouts and treat symptoms when they happen.

Rosacea— Frequent redness (rinsing) of the face; Small red lines under the skin; Swollen eyes/eyelids, swollen nose, and thicker skin. Your doctor can usually diagnose rosacea with a thorough medical history and physical examination. There is no cure for rosacea, but it can be treated and controlled.

Skin Cancer—Skin cancer is the most common form of cancer in the United States. The two most common types are basal cell cancer and squamous cell cancer. They usually form on the head, face, neck, hands, and arms. Another type of skin cancer, melanoma, is more dangerous but less common.

Wrinkles—Your skin changes as you age. You might notice wrinkles, age spots, and dryness. Sunlight is a major cause of skin aging. Cigarette smoking also contributes to wrinkles. The wrinkling increases with the number of cigarettes and years a person has smoked. Many products claim to revitalize aging skin or reduce wrinkles, but the Food and Drug Administration has approved only a few for a sun-damaged or aging skin. Various treatments soothe dry skin and reduce the appearance of age spot.