1. Homeostatic Imbalances of Skin

2. Homeostatic Imbalances of Skin
When skin rebels, it is quite a visible revolution.
Loss of homeostasis in body cells and organs reveals itself on the skin, sometimes in startling ways.
skin can develop more than 1000 different conditions and ailments. The most common skin disorders are bacterial, viral, or yeast infections.
A number of these are summarized in Related Clinical Terms. Less common, but far more damaging to body well-being, are skin cancer and burns, considered next.

3. Related Clinical Terms
Albinism (al′bĭ-nizm; alb = white) Inherited condition in which melanocytes do not synthesize melanin owing to a lack of tyrosinase.
albino’s skin is pink, the hair pale or white, and the irises of the eyes unpigmented or poorly so.

4. Related Clinical Terms
Boils and carbuncles (kar′bung-klz; “little glowing embers”) Inflammation of hair follicles and sebaceous glands in which an infection has spread to the underlying hypodermis; common on the dorsal neck. Carbuncles are composite boils.
A common cause is bacterial infection.

5. Related Clinical Terms
Cold sores (fever blisters) Small fluid-filled blisters that itch and smart; usually occur around the lips and in the mucosa of the mouth; caused by a herpes simplex infection.
The virus localizes in a cutaneous nerve, where it remains dormant until activated by emotional upset, fever, or UV radiation.

6. Related Clinical Terms
Contact dermatitis Itching, redness, and swelling, progressing to blister formation; caused by exposure of the skin to chemicals (e.g., poison ivy oleoresin) that provoke an allergic response in sensitive individuals.

7. Related Clinical Terms
Decubitus ulcer (de-ku′bĭ-tus) Localized breakdown and ulceration of skin due to interference with its blood supply.
Usually occurs over a bony prominence, such as the hip or heel, that is subjected to continuous pressure; also called a bedsore.

8. Related Clinical Terms
Epidermolysis bullosa (EB) A group of hereditary disorders characterized by inadequate or faulty synthesis of keratin, collagen, and/or basement membrane “cement” that results in lack of cohesion between layers of the skin and mucosa; a simple touch causes layers to separate and blister. For this reason, EB victims are called “touch-me- nots.” In severe cases fatal blistering occurs in major vital organs. Because the blisters rupture easily, victims suffer frequent infections; treatments are aimed at relieving the symptoms and pre-venting infection.

9. Related Clinical Terms
Impetigo (im″pĕ-ti′go; impet = an attack) Pink, fluid-filled, raised lesions (common around the mouth and nose) that develop a yellow crust and eventually rupture.
Caused by staphylococcus infection, contagious, and common in school-age children.

10. Related Clinical Terms
Mongolian spot Blue-black spot appearing in the skin of the sacral region, which results from the unusual presence of a cluster of melanocytes in the dermis; the light-scattering effect of the epidermis causes these dermal melanin-containing regions to appear blue. Disappears by age 3 or 4.

11. Related Clinical Terms
Psoriasis (so-ri′ah-sis) A chronic condition characterized by raised, reddened epidermal lesions covered with dry silvery scales that itch, burn, crack, and sometimes bleed or become infected. When severe, it may be disfiguring and debilitating.
Autoimmune attack in affected regions is suspect; attacks are often triggered by trauma, infection, hormonal changes, and stress. Phototherapy with UV light in conjunction with chemotherapeutic drugs provides some relief.

12. Related Clinical Terms
Vitiligo (vit″ ĭ-li′go; viti = a vine, winding) The most prevalent skin pigmentation disorder, characterized by a loss of melanocytes and uneven dispersal of melanin, i.e., unpigmented skin regions (light spots) surrounded by normally pigmented areas.
Probably an autoimmune disorder