Homeostatic Imbalances of Skin

Homeostatic Imbalances of Skin

### Infections and Allergies

Athlete’s foot: Caused by fungal infection (Tinea pedis).

• Symptoms include itchy, red, peeling skin between the toes.

-Fungi thrive in warm, moist environments, making footwear a common source.

Boils (furuncles) and carbuncles: Caused by inflammation of hair follicles.

• Carbuncles are clusters of boils caused by bacteria.

-Often caused by Staphylococcus aureus bacteria.

Cold sores (fever blisters): Caused by human herpesvirus 1.

• Symptoms include blisters that itch and sting.

- Virus remains dormant and can be reactivated by stress, sunlight, or fever.

Contact dermatitis: Caused by exposure to chemicals that provoke allergic responses.

• Symptoms include itching, redness, and swelling of the skin.

- Common irritants include poison ivy, nickel, and certain cosmetics.

Impetigo: Caused by bacterial infection.

• Symptoms include pink, fluid-filled raised lesions around the mouth and nose.

- Highly contagious and common in children.

Psoriasis: Triggered by trauma, infection, hormonal changes, or stress.

• Symptoms include red, epidermal lesions covered with dry, silvery scales that itch, burn, crack, or sometimes bleed.

  • Chronic autoimmune condition affecting the skin.

Burns

- Tissue damage and cell death caused by heat, electricity, UV radiation, or chemicals.

Associated dangers:

• Protein denaturation and cell death.
  -Destroys enzymes and structural proteins.

• Dehydration and electrolyte imbalance.
  -Loss of fluids leads to imbalance.

• Circulatory shock.
  -Reduced blood volume impairs circulation.

• Result in loss of body fluids and infection from the invasion of bacteria. -Compromised skin barrier increases infection risk.

  • Extent of a burn is estimated using the rule of nines.

Rule of Nines

• The body is divided into 11 areas for quick estimation.

• Each area represents about 9 percent of total body surface area.

- The area surrounding the genitals (the perineum) represents 1 percent of body surface area.

Body Area Percentage:

• Anterior and posterior head and neck: 9\%

• Anterior and posterior upper limbs: 18\%

• Anterior and posterior trunk: 36\%
  -Anterior trunk: 18\%.

• Perineum: 1\%

• Anterior and posterior lower limbs: 36\%

#### Degrees of Burns

First-degree burn (superficial burn):

• Only the epidermis is damaged.
  -Causes minor pain and redness.

• Skin is red and swollen.

-Heals within a few days.

Second-degree burn (superficial partial-thickness burn):

• Epidermis and superficial part of the dermis are damaged.
  -Blisters form as fluid collects between epidermis and dermis.

• Skin is red, painful, and blistered.
  -Can take weeks to heal and may leave scars.

• Regrowth of the epithelium can occur.

-As long as hair follicles and sweat glands are intact.

Third-degree burn (full-thickness burn):

• Destroys epidermis and dermis; burned area is painless.
  -Nerve endings are destroyed.

• Requires skin grafts, as regeneration is not possible.
  -Due to loss of skin structures.

• Burned area is blanched (gray-white) or black.

-Appearance varies based on severity and tissue damage.

Fourth-degree burn (full-thickness burn):

• Extends into deeper tissues (bone, muscle, tendons).
  -May involve significant functional impairment.

• Appears dry and leathery.

• Requires surgery and grafting.

• May require amputation.

Criteria for Critical Burns

• Over 30 percent of the body has second-degree burns.

• Over 10 percent of the body has third- or fourth-degree burns.

• Third- or fourth-degree burns of the face, hands, feet, or genitals.

  • Affects breathing, eating or mobility.

• Burns affect the airways.

  • Inhalation injury can cause respiratory failure.

• Circumferential (around the body or limb) burns have occurred.

  • Can cause compartment syndrome due to swelling.

Skin Cancer

• Most common form of cancer in humans.

• The most important risk factor is overexposure to ultraviolet (UV) radiation in sunlight and tanning beds.

- UV radiation damages DNA in skin cells.

Cancer classification:

• 
  Benign: The neoplasm (tumor) has not spread.
  -Usually not life-threatening.

• Malignant: The neoplasm has invaded other body areas. -Can be life-threatening if not treated.

  • Mitosis gone wild is the basis for cancer. These cells lack normal control of cell division and divide quickly, resulting in errors during DNA replication, mitosis, or both. Cells experiencing rapid, uncontrolled growth become cancerous and can metastasize (spread) to other parts of the body.

Common Types of Skin Cancer

• Basal cell carcinoma

• Squamous cell carcinoma

• Malignant melanoma

Basal Cell Carcinoma

• Least malignant and most common type of skin cancer.

• Arises from cells in the stratum basale that are altered so that they can no longer make keratin.

  • Keratin is a structural protein in the skin.

• Lesions appear as shiny, dome-shaped nodules that develop a central ulcer.

  • Often found on sun-exposed areas like the face and neck.

Squamous Cell Carcinoma

• Believed to be induced by UV exposure.

• Arises from cells of the stratum spinosum.

• Lesions appear as scaly, reddened papules that gradually form shallow ulcers.

  • Can appear on the scalp, ears, and hands.

• Early removal allows a good chance of cure.

• Metastasizes to lymph nodes if not removed.

Malignant Melanoma

• Most deadly of skin cancers but accounts for only 5 percent of skin cancers.

• Cancer of melanocytes.

  • Melanocytes produce melanin, the pigment responsible for skin color.

• Metastasizes rapidly to lymph and blood vessels.

  • Early detection is crucial for survival.

• Detection uses the ABCDE rule for recognizing melanoma.

#### ABCDE Rule for Melanoma

A = Asymmetry: Two sides of the pigmented mole do not match.

B = Border irregularity: Borders of the mole are not smooth.

C = Color: Different colors in the pigmented area.

D = Diameter: Spot is larger than 6 millimeters in diameter.

E = Evolution: One or more of the ABCD characteristics is evolving.

Developmental Aspects of Skin and Body Membranes

• Lanugo, a downy hair, covers the body by the fifth or sixth month of fetal development but disappears by birth.

  • Helps to hold the vernix caseosa in place.

• Vernix caseosa, an oily covering, is apparent at birth.

  • Protects the fetus's skin from amniotic fluid.

• Milia, small white spots, are common at birth and disappear by the third week.