1. Vellus hair - fine, faint, covers most of the body (except palms, soles of feet, dorsa of the distal parts of the fingers), umbilicus, glans penis and inside the labia).
2. Terminal hair - darker, thicker - grows on scalp, eyebrows, axillae, pubic area, face, chest of male
1. Epidermis - Thin, tough outer layer (keratinized), avascular, melanin in basal cell layer
2. Dermis - Connective tissue,
collagen, Vascular
3. Hypodermis / subcutaneous tissue- Fat cells, Cushion, Generates heat, Store calories
4. Also, includes hair, sebaceous and sweat glands
Hypopigmentation (loss of color) and hyperpigmentation (increase in color).
Vitiligo - patchy depigmentation from destruction of melanocytes
Also, generalized change suggests systemic illness:
1. Cyanosis- hypoxia, deoxygenated blood- Cardiac & Respiratory function issues
Central
cyanosis: lips, oral mucosa, tongue
Peripheral cyanosis: nails, hands, feet ( all also w/ central)
2. Jaundice - Reflects GI and liver dysfunction or hemolytic disease after severe burn, some infections- increased serum bilirubin >2-3 mg/mL, check sclera
3. Pallor - pale skin, associated w/ anemia
fingernails, lips (pale?), mucus membranes of mouth, palpebral conjunctiva (lining of the lids - anemic looks very pale)
4. Consider allergic rxn to new food (infants) or drug rxn
Newborn skin- thin, smooth, elastic, skin covered with lanugo (fine downy hair, which replaced to fine vellus hair in first few months)
1. More permeable than adult, greater risk of fluid loss
2. Sebum (holds water in skin) is present for first few weeks of life, produces milia and cradle cap. Sweat glands mature at one month (book says 2 months) But sebaceous glands decrease until puberty
3. Temperature regulation ineffective - less fat (subQ layer
inefficient), unable to contract/shiver - hypothermia. Eccrine sweat glands don't work until 2 months (cannot sweat in high heat)
Desquamation at birth (fully cooked - 41 weeks). Desquamation - to scrape the scales off a fish"), also called skin peeling, is the shedding of the outermost membrane or layer of a tissue, such as the skin
1. Skin loses elasticity, thus folds and sags.
2. By 70s/80s, skin is parchment thin, lax, dry and wrinkled.
3.
Epidermis thins and flattens (chemicals get easier access into body)
4. Loss of elastin, collagen, and subQ fat and reduction of muscle tone.
5. Loss of collagen increases risk of shearing, tearing injuries
6. Less sebaceous gland activity (decrease in number and function),less sweating, greater risk of heat stroke
7. Vascularity of skin decreases (decreased nutrients too) and vascular fragility increases (minor trauma can produce dark red area = senile purpura)
8. Worse if
smoked and were in sun often- coarse wrinkling, decreased elasticity, atrophy, speckled and uneven coloring, more pigment changes, yellowish,leathery texture
9.Thinning of hair, number of functioning melanocytes decreases. Genetics determines onset of graying and number of gray hairs
10. Rogue whiskers - unwanted facial hair (female -decrease in estrogen, testosterone unopposed)
11.Hair migrates- men have symmetric W shaped balding in frontal areas
12. Nails grow slower- lusterless
and longitudinal ridges from trauma at matrix
13. Skin cancers
Macule 1.0 cm or less, solely a color change, flat and circumscribed (i.e. freckles, petechiae, measles, scarlet fever, flat nevi
Patch > 1.0 cm (i.e.mongolian spot, vitiligo, cafe au lait spot, chloasma, measles rash)
Nodule = Solid, elevated, hard or soft, > 1.0 cm, may go deeper into dermis than papule (i.e. xanthoma, fibroma, intradermal nevi)
Tumor = Larger than few cm in diameter, firm or soft, deeper into dermis, may be benign or malignant (i.e. lipoma, hemangioma)
Papule= up to 1.0 cm diameter, can feel (i.e. solid, elevated, circumscribed (i.e. elevated nevus/mole, lichen planus, molluscum, wart (verruca)
Plaque = > 1.0 cm; , papules coalesce to form surface elevation >1cm. plateaulike, disk- shaped lesion crust, scale (i.e. psoriasis, eczema lichen planus)
Vesicle = blister, up to 1 cm, clear serum flows if wall is ruptured (i.e. herpes simplex, early varicella (chickenpox), contact dermatitis, herpes zoster/shingles)
Bulla = Greater than 1 cm, single chambered (unilocular), superficial in epidermis, thin walled and ruptures easily (i.e. friction blister, contact dermatitis, pemphigus burns)
Keloid= Benign excess of scar tissue beyond sites of original injury surgery, acne, ear piercing,
tattoos, burns. looks like smooth, rubbery, shiny, clawlike, feels smooth and firm. Can occur months to years after initial trauma. Most common in 10-30 years. higher incidence in Blacks, Hispanics, Asians
Found in ear lobes, back of neck, scalp, chest, back
Malignant Melanoma =potentially lethal lesions, transformations of melanocytes. Can arise from preexisting nevus or de novo (starting from the beginning, brand new). Can be tan, black, pink-red or
mixed pigmentation. Irregular, notched borders. Can have scaling, flaking, oozing texture.
Common locations: trunk, back, legs in women, palms, soles of feet and nails (in dark-skinned people).
Risk factors: UV, indoor tanning, family history
Most common cancer in women 25-29 and 2nd most common (after breast cancer) in 30-34 women