The integumentary system (or skin) is the largest organ of the body. It weighs 6 lbs. to 9 lbs. with a surface area of about two square yards. The skin serves as a protection from harmful bacteria and viruses for all internal body parts. The integumentary system maintains body temperature and senses heat, cold and moisture in the environment.
Dermatitis
Dermatitis describes a variety of conditions that cause inflammation of the skin. Merck.com, an online medical library, says seborrheic dermatitis is a chronic inflammation that appears in infants and elderly people. Symptoms of seborrheic dermatitis present as yellow, greasy scales on the scalp that creates a crusted scalp rash known as cradle cap. Atopic dermatitis presents as chronic inflammation that itches and develops into red, crusted rashes.
Impetigo
Impetigo is a bacterial skin infection caused by group A streptococcus or staphylococcus aureus. An infection occurs when the skin barrier is broken and bacteria get into the skin. Skin that's irritated from conditions such as poison ivy and eczema provide a favorable breeding environment for the bacteria. Blisters appear first, followed by oozing and crusting. Impetigo is highly contagious and spreads easily to other parts of the body or to another person.
Shingles
Shingles is a skin rash caused by the varicella-zoster virus, the same virus that causes chickenpox. Anyone who has had chicken pox has the varicella-zoster virus resident in the body. It may remain dormant indefinitely, or it may reactivate. The National Institute of Neurological Disorders and Stroke says that upon reactivation, the virus moves to the nerve fibers supplying the skin. Symptoms include itching, numbness or burning pain. About a week after the initial symptoms, the shingles rash appears as fluid-filled blisters.
Rosacea
Rosacea is a chronic skin disorder that primarily affects the facial skin. The National Rosacea Society says facial flushing is an early sign of rosacea. The redness is intermittent. Other symptoms of rosacea include a persistent redness that appears like permanent sunburn, small red pimples that burn and small visible blood vessels. Secondary symptoms include dry facial skin, skin thickening--especially on the nose--facial swelling and raised red patches.
Psoriasis
Psoriasis, a chronic autoimmune disease, is not contagious. Of the five types of psoriasis--plaque, guttate, inverse, pustular and erythrodermic--the most common is plaque psoriases. Symptoms include raised red lesions covered with dead skin cells. The most common age for onset of psoriasis is between 15 and 35.
