Skin, Hair, and Nails Anatomy

Skin, Hair and Nails

• The skin acts as a protective barrier against environmental factors like bacteria, viruses, and dehydration.
• Keratinocytes, which produce keratin, are the main components. Keratin strengthens the skin

Skin Layers

Epidermis

• The epidermis consists of stratum corneum, stratum lucidum, stratum granulosum, and stratum germinativum from outermost to innermost.
• Stratum germinativum (basal cell layer) is where mitosis occurs and melanocytes produce melanin.
• Stratum corneum provides a protective barrier, cells rising will convert cytoplasm to keratin, resulting in a rough, horny texture, this layer constantly sheds.

Dermis

• The dermis is the middle layer of the skin.
• Primarily consisting of connective tissue, mainly collagen.
• The dermis provides support and nourishment to the epidermis.
• Thicker, offers strength, elasticity, and support.
• Contains blood vessels, nerves, muscle, sweat glands, sebaceous glands, and hair follicles.

Sebaceous Glands

• Produce sebum through hair follicles, making skin oily and preventing water loss.

Sweat Glands

• Eccrine glands are smaller, coiled tubules that open to the skin surface and are located over the entire skin.
• Apocrine glands. larger, and open into hair follicles, found mainly in axillae, areolae of the breasts, and genital area, relatively small and nonfunctional until puberty, produce thick secretions that react with bacteria on the surface of the skin causing body odor.

Subcutaneous Layer (Hypodermis)

• The deepest layer of the skin which consists mostly of adipose tissue and connective tissue.
• Contains blood vessels, lymphatic vessels, and nerves, supplying nutrients and removing waste from the skin.
• This layer is used for insulin or vaccine injections because of its good supply and slow absorption.
• The hypodermis thickness varies depending on age, sex, and body region and excess fat contributes to obesity.

Hair

• Composed of keratin, can be fine (vellus hair) or thicker (terminal hair)
• The hair shaft is the visible part, and the hair root anchors within the follicle. The hair follicle is a tube-like structure that produces and nourishes hair growth
• The cuticle is the outermost layer providing protection. The cortex provides strength and color and the medulla is the innermost soft layer.

Nails

• Primarily composed of keratin
• Clear with a highly vascular bed of epithelial cells underneath

Developmental Considerations

Infants

• Helps regulate body temperature and Lanugo is fine, soft hair present at birth
• Skin is thinner, less fat, making them more prone to dehydration and hypothermia.

Pregnancy

• Linea nigra is a line down the midline of the abdomen
• Chloasma appears on the face
• Striae gravidarum are stretch marks
• Melasma causes dark blotchy patches due to increased melanin production from pregnancy hormones.

Aging

• Stratum corneum thins, with loss of collagen, elastin, and fat, as well as decreases in sebaceous and sweat glands.
• Skin becomes more prone to dehydration and hypothermia.

History of Skin Disease

• Identify the past or current skin condition
• Determine the nature, duration, and severity of the condition
• Investigate if there were treatments used, including topical or oral medications, phototherapy, or home remedies, assess response to treatment and whether the condition was resolved, recurrent, or persistent.
• Determine if there are known allergies to medications, skincare, food, or environmental factors to prevent allergic contact dermatitis or other hypersensitivity reactions.
• Identify any tattoos or birthmarks, posing risks such as allergic reactions, infections, or scarring.
• Familial history of dermatological conditions is needed.

Change in Pigmentation

• May suggest systemic illness (jaundice).
• Change in a mole can indicate melanoma and should be evaluated for potential malignancy.

Rash or Lesion

• Onset, location, spread, character or quality, duration, aggravating or alleviating factors, the patient’s perception

Medications

• Prescription and over-the-counter medications may indicate allergy or medication

Hair Loss or Growth

• Gradual or sudden hair loss vs unusual hair growth

Change in Nails

• Abnormalities may indicate systemic conditions such as anemia or liver disease

Exposure to Hazards

• May be environmental or occupational factors
• Exposure to plants or animals

Self Care

• The patient's cosmetics, soaps, and chemical exposure

Physical Examination – Color

• General pigmentation should be evenly distributed throughout the body
• Underlying conditions can cause pallor or anemia
• Benign Pigmented Areas include freckles, nevi

Changes in Color in Light Skinned People

• Pallor presents as as pale, white color due to decreased blood flow (vasoconstriction) or decreased hemoglobin
• Erythema is redness due to increased blood flow (vasodilation)
• Cyanosis is a bluish or purplish hue due to decreased perfusion of tissues
• Jaundice presents as a yellow or orange hue due to increased bilirubin in the blood

Temperature

• Hyperthyroidism increases temperature

Moisture

• Diaphoresis may occur during fever or exercise

Mobility and Turgor

• Mobility is the ease of skin rising when pinched
• Turgor is how quickly the skin returns back to place
• Slow turgor can indicate dehydration, with "tenting" indicating severe dehydration

Lesions

• Lesions are any traumatic or pathological change in skin
• Nodules should be gently Rolled between fingers to assess depth
• Ultraviolet light should be used if fungal infection is suspected

Edema

• Defined as the presence of excess interstitial fluid, with areas appearing swollen, shiny, and taut
• Characterized as pitting or non-pitting

Pressure Ulcers

• Also known as pressure sores or bedsores, are injuries to the skin and underlying tissue caused by prolonged pressure
• Typically affect people confined to bed or who sit in a chair or wheelchair for long periods

Nursing Responsibility

• Use repositioning schedules (every 15 minutes when on chair or every 2 hours when on bed)
• Use pressure mattress or chair cushion
• Use lifting devices as directed to reduce shear (trapeze bar for patients, or lifts for family, if necessary)
• Use positioning with pillows or wedges to avoid bony prominence contact with surfaces and to maintain body alignment
• For those who are bedbound, avoid elevating the head of bed beyond 30 degrees except for brief periods