Dermatology

Intro I

what is the largest organ in the body?

what system is this a part of?

skin
integumentary system

functions of the skin

cover entire body

protection

regulates body temperature

sensory organ 

vitamin D synthesis

produces keratin

keratinocytes

a protein which is the main substance found in skin, hair, and nails

keratin

produce the pigment melanin when exposed to sunlight

melanocytes

what acts as a sheild agains uv radiation and determines skin color

melanin

macrophages that initiate immune response and provide defense against environmental foreign proteins

langerhans cells

touch receptors

found at the junction of the epidermis and dermis

merkel cells

what is the thickest division of skin

dermis

what is the dermis composed of

collagen and elastin fibers

what is the dermis rich in

blood vessels

sweat glands

lymphatics

sebaceous glands

nerves

what does the dermis include

hair follicles with their sebaceous gland attachments

what are the two layers of the dermis

papillary layer

reticular layer

what is found in the papillary layer

capillaries and neurons

how much of the dermis does the reticular layer make up

~80%

what is found in the reticular layer

collagen bundles

hair follicles

sweat glands

what is another name for the subcutaneous layer of the skin

hypodermis

hypodermis is a layer of _____

fat

what does the hypodermis house

larger blood vessels and nerves

what is the hypodermis important in

regulation of temperature

any pathological change in the skin

lesion

pathognomonic

can be diagnostic of what disease is present

what often gives important clues for lesions

chronology

what is the most important part of history taking and physical exam of a lesion

location

primary lesion

develop from previously “normal” skin

secondary lesion

develops from primary lesion

flat, non-palpable, <2 cm

primary

macule

>2 cm with color different than surrounding skin

primary

patch

example of a macule

cafe-au-lait

examples of patch

vitiligo
mongolian spot

<1cm lesion, raised, palpable 

primary

papule

example of papule

verruca vulgaris

1-5 cm firm lesion, palpable

primary

nodule

>5 cm solid raised lesion

primary

tumor

>1 cm raised (usually flat topped) lesion; confluence of papules

primary

plaque

example of plaque

psoriasis

<1 cm thin walled, fluid-filled lesion

primary

vesicle

example of vesicle

herpes simplex

>1 cm fluid-filled lesion

primary

bulla

raised lesion containing purulent (pus like) exudate

primary

pustule

soft, raised lesion filled with semisolid or liquid material

primary

cyst

raised flat topped edematous papule or plaque that is transient

primary

wheal

what are wheals common in

allergic reactions

examples of wheal

urticaria

dermatographia

tiny, circumscribed deposits of blood that do not blanch

primary

petechiae

what does it mean to not blanch

color remains when pressed on

larger areas of blood deposits under the skin, various etiologies

primary

ecchymosis

example of ecchymosis

common bruise

dilated, superficial blood vessels

primary

telangiectasia

dead epidermal cells produced by abnormal keratinization and shedding

secondary

scales

collection of dried serum and cellular debris

secondary

crusts

a more common term for crusts

scab

open lesion of the skin or mucus membrane with the loss of the epidermis and upper papillary layer of dermis

secondary

ulcer

what do ulcers usually heal with

a scar

loss of epidermis, superficial

secondary

erosion

linear ulcer or crack like lesion

secondary

fissure

linear abrasions of epidermis usually caused by scratching (self-inflicted)

secondary

excoriations

thickened area of skin caused by chronic scratching or rubbing

secondary

lichenification

change in skin due to trauma or inflammation

secondary

scar

other terms for scar

cicatrix

eschar

hypertrophied scars

secondary

keloid

there is loss of normal skin texture with thinning and wrinkling

secondary

atrophy

setting

what were you doing when you first noticed the lesion?

chronology

when did the lesion start and how has it changed?

is it constant or intermittent?

location

where is it?

has it spread?

quality

what does it look like?

is it bleeding/draining?

quantity

how many?

aggravating/alleviating factors

worse with heat/cold?

tried anything for it?

any recent changes in meds, detergents, foods, skin products?

associated manifestation?

itching, bleeding, general symptoms

past medical history

anything like this before?

chronic illness

family history

social history

physical exam

appropriate exposure

good light

magnification

ruler

gloves

type of lesion

one of the primary/secondary lesions

shape

round, oval, irregular, umbilicated

color

erythematous, pale, cyanoic

arrangement

referring to groupings of the lesion (linear, annular)

distribution or pattern

generalized, localized, isolated, intertriginous, symmetrical

margination

well defined or ill defined

size

use a ruler

what is the most common bacteria infection in children

impetigo

where is impetigo located

superficial infection of the epidermis

what causes impetigo

staphylococcus aureus

streptococcus pyogenes

is impetigo contageous

yes

what does it mean by saying that impetigo is autoinoculable 

can move to another part of the body through contact

is impetigo painful

no

two types of impetigo

bullous

non-bullous

which type of impetigo accounts for about ~70% of cases

non-bullous

lesion chronology of non-bullous impetigo

start as small vesicles or pustules that rupture and become honey-colored crusts on an erythematous base

common locations of non-bullous impetigo

become confluent mostly under nose, cheeks, lips, and chin

who does non-bullous impetigo often occur in

patients where there has been skin trauma or there is an underlying skin disorder or disease

risk factors for non-bullous impetigo

participation in contact sports, poor hygiene, crowded living conditions, hot-humid weather

what else is often present in non-bullous impetigo

mild regional lymphadenopathy 

chronology of bullous impetigo

lesions appear suddenly as superficial fragile bullae, which rupture and drain clear or yellow fluid

where does bullous impetigo usually spread

face, trunk, extremities and buttocks

perineal region of infants

what type of skin does bullous impetigo typically occur on

previously normal skin

which type of impetigo is more contagious

non-bullous

are there honey colored crusts on bullous impetigo

no

typical route for localized impetigo

topical antibiotics

topical antibiotics used for localized impetigo

mupirocin (Bactroban) ointment apply to affected area TID x 10 days

retapamulin (Altabax) topical is an alternative but very expensive

typical route for widespread impetigo

oral antibiotics 

types of oral antibiotics for widespread impetigo

cephalexin (Keflex) 500 mg T tab BID or 250 mg T tab QID

doxycycline (Vibramycin) 100 mg T tab BID

Children- cephalexin dosed by weight