CLIN PATH: EXAM #2 (DERM - LEC I)

Skin

________ is the most accessible organ of the human body

adnexal structures

Skin is distinct from mucosa in that it contains ________________ such as the eccrine units that exude sweat and the folliculosebaceous units that produce hairs and oils

Epidermis

______________ – superficial, tough, protective

• Stratified epithelium (keratinocytes)

• Melanocytes, exocrine sweat glands open here

• Has 5 layers

Dermal

__________ – epidermal junction

•Undulating, basement membrane

Dermis

___________ – semi-fluid, binds the body together

• Nerve endings, oil & sweat glands, hair follicles, blood & lymph vessels, connective tissue

Melanocytes and Langerhans cells

________________________ are dendritic cells that are intercalated among the keratinocytes of the epidermis

Melanocytes

__________________, which are positioned in the basal layer, synthesize a reddish-brown biochrome, melanin

Langerhans cells

_______________ share a similar arborized morphology (to Melanocytes) but are positioned in the midspinous layer

Langerhans cells

________________ are bone marrow–derived antigen-presenting cells

connective tissue gel

The dermis consists of a ___________________ composed largely of proteins and mucopolysaccharides

collagen types I and III, and a network of elastic microfibrils

The Dermis is composed of ________________________ is also woven throughout the full dermal thickness

Dermis

Fibrocytes are ubiquitous, and there are also mast cells and dendritic immune cells arrayed throughout the ________

Macule

________________:

• Area of increased or decreased pigmentation WITHOUT elevation or depression

• <1 cm

• Not palpable

• In superficial layers only

Patch

__________________:

• Macular type lesion

• Circumscribed

• >1 cm in diameter

Papule

____________________:

• Superficial, solid lesion

• <0.5 cm in diameter

• Often occur in clusters

• Can accompany rashes

Papule

_________________:

• Inflammation

• Infected/ abraded skin

• Accumulated secretions

• Infection

• Disseminated histoplasmosis

• Hypertrophy of skin cells

• Acne

Plaque

______________:

• Plateau-like elevation with a surface area > it's height

• Frequently forms by a confluence of papules

• >1 cm in size

Lichenification

____________ – the surface is rough & thickened

•Accentuates the normal skin lines

•Resembles a tree bark

Vesicle

• Small fluid filled lesion on or below the skin

• Circular lesions

• <1 cm in diameter

Bulla

•Circumscribed collection of free fluid

•> 1 cm

pustule

•A vesicle or bulla containing purulent fluid is known as a _________

pustule

___________________:

•Superficial skin cavity containing purulent exudate

•May be yellow, white, green-white, or hemorrhagic

blisters

Both vesicles and bulla are called _________

Blisters (Vesicle or Bulla)

When the epidermis separates from the dermis, a pool of lymph and other body fluids collect between the 2 layers while the skin re-grows from underneath. What is this called?

Blisters (Vesicle or Bulla)

Etiology of __________________:

•Chemical or allergic rxn

•Physical injury (heat, frostbite, friction)

nodules

____________:

• Solid, circular lesion

• > 1 cm

• Usually invades the epidermis & lower dermis

Wheal

_________________ (AKA: urticarial exanthem, urticaria)

- Rounded, or flat topped, edematous plaque

- Well demarcated

- No scaling

- No epidermal involvement

- Color varies

- Shape: round, oval, gyrate, annular or serpiginous

Wheal

An allergic response to allergens such as drugs or insect bites will appear as what kind of skin response?

Darier's sign

_______________:

•Gentle rubbing or stroking of the lesions, is followed by local itching, erythema and weal formation within 2-5 min

Dermatographism

___________________:

• "writing on the skin”. It is a very common localized hive reaction.

Cyst

_______________:

•Encapsulated lesion filled with fluid or semisolid material

•Elevated, circumscribed, palpable

•An enclosed sac with a distinct membrane lining

•

Abscess

________________: A collection of pus

Crusts

________________:

•Dried serum or exudates on the skin surface

•Blood appears brown

•Serum is honey colored

•Pus is a combo of yellow & green

•Present after blisters rupture

Scales (Desquamation)

_______________:

• Abnormal areas of stratum corneum

•An increased rate of epidermal cell proliferation

•May be adherent or loose, large sheet-like areas or tiny particles

Erosion

_____________:

•Skin defect with loss of epidermis only

•Heals w/o a scar

Ulcer

•Skin defect with a loss of epidermis & upper layer of the dermis

•May extend into lower layers

•Always heals with scar tissue

Telangiectasias

__________________:

•Small enlarged blood vessels near the surface of the skin

•Usually mms in size

•On nose, cheeks & chin

•

Petechiae

•One petechia

•Small red or purple spot on the body

•< 3 mm

Petechiae

•Etiology:

•Minor hemorrhage (broken capillary)

•Thrombocytopenia

•↓ platelet function

Purpura

_________________:

•Larger red or purple discolorations on the skin 3mm-10mm

Purpura

______________ Etiology:

•Bleeding under the skin

Ecchymosis

________________:

•Capillary damage allows blood to extravasate into surrounding tissues

•> 1 cm in diameter

Ecchymosis

_________________: Etiology:

•Usually blunt trauma

Petechiae, Purpura, and Ecchymosis

________________ do NOT blanch with pressure

Tumor

________________:

•Solid lesion with elevation & depth

•Usually involves epidermis & dermis, possibly SC tissue

•> 2 cm in diameter

•+/ - pigmentation

Perivascular dermatitis

________________:

• Perivascular inflammatory infiltrate w/o significant epidermal involvement

• EX: hives

Spongiotic dermatitis

_______________:

•Associated with intercellular epidermal edema (spongiosis)

• EX: allergic contact dermatitis

Psoriasiform dermatitis

_________________:

• Associated with epidermal thickening from elongated rete ridges

• EX: psoriasis

Interface dermatitis

_______________:

•Cytotoxic rxn that affects the dermis and epidermis

•Characterized by vacuoles and lymphocyte infiltrates

• EX: lichen planus

Vesiculobullous dermatitis

_______________:

• Intradermal or subepidermal cleavage

• EX: bullous pemphigoid

Vasculitis

__________________:

• Damage to cutaneous vessel walls

• EX: leukocytoclastic vasculitis

Folliculitis

_______________:

• Rxn directed against colliculo-sebacous units

• EX: acne folliculitis

Nodular dermatitis

_________________:

• Nodular or diffuse dermal infiltrate w/o significant epidermal changes

• EX: cutaneous sarcoidosis

Panniculitis

___________________:

• Involves the sc fat

• erythema nodosum

Psoriasis

____________________:

• Commonly affects the nail bed and matrix, yielding pitted or markedly thickened dystrophic nails.

• Mucosal surfaces are spared.

______________:

• "Squirting dermal papillae" (Migration of neutrophils from the dermal papillae into the overlying epidermis)

psoriatic arthritis

Only extracutaneous manifestation of psoriasis is ________________: a deforming, asymmetric, oligoarticular arthritis that can involve small or large joints.

Interface dermatitis

________________:

• Inflammatory skin disease in which the junction between the papillary dermis and epidermis is obscured.

Interface dermatitis

_________________:

• Lymphocytes attack the basal layer of epidermis causing vacuolar change in the basal cells or necrosis of basal keratinocytes.

Interface dermatitis

________________:

•Lichen Planus (chronic interface dermatitis)

•Erythema Multiforme (acute interface dermatitis)

vacuolar change

Lymphocytes attack the basal layer of epidermis causing _____________ in the basal cells or necrosis of basal keratinocytes.

vacuoles

Injury to basal keratinocytes and other structures produces tiny ___________ along the dermoepidermal junction, on both sides of the basal lamina

T-cell mediated damage to keratinocytes and remodeling of the basement membrane zone

The pathophysiology of many of the diseases in which interface dermatitis occurs is similar. What is it?

Lichen planus

______________:

•Develops in adulthood

•Women > men

• Etiology: mostly unknown

Drugs that cause Lichen planus

________________:

•Therapeutic gold

•Antimalarial agents (Quinine, Chloroquine)

•Penicillamine (cupramine)

•Thiazide diuretics

•Antibiotics (Tetracycline, Isoniazid, Streptomycin)

•Anticonvulsants (Carbamazepine, Phenytoin)

Lichen planus

________________: Begins with a dense infiltrate of T lymphocytes in the papillary dermis & superficial dermis:

• Keratinocytes & melanocytes are damaged

Lichen planus

_________________:

•Vacuoles appear in the lower epidermis

•Colloid bodies are also present

•Mature lesions are composed of CD8 cytotoxic T cells

Erythema Multiforme

_______________: A cell mediated immune rxn that results in necrosis of epidermal keratinocytes

Erythema Multiforme

_____________ Etiology:

•HSV infection

•Rxn to meds

•Idiopathic