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DD & BL Unit III / Final Exam > Dermatology > Flashcards

Flashcards in Dermatology Deck (133)
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1
Q

Atopic Dermatitis - Diagnosis

A

Itchy skin + 3 or more of the following:

Involvement of skin creases or face
History of asthma or hay fever
History of dry skin 
Visible flexural eczema 
Onset < 2 years
2
Q

Atopic Diathesis

A

Atopic Dermatitis
Asthma
Allergic Rhinitis

3
Q

Atopic Dermatitis - Pathogenesis

A

Disruption of skin barrier, likely due to filaggrin mutation

Secondary infection with Staph aureus often exacerbates inflammation

Patients often show elevated serum IgE and eosinophilia

4
Q

Atopic Dermatitis - Clinic Presentations by age group

A

Infants - dry, red, scaly areas confined to cheeks; flushes with cold

Childhood - erythematous papules, redness, scaling, characteristic involvement of flexural skin

Adult - characteristic involvement of eyelids & hands

5
Q

Atopic Dermatitis - Associated Features

A
Dry Skin (Xerosis) 
Ichthyosis vulgaris (plate-like dry skin) 
Keratosis Pilaris (bumpy skin) 
Hyperlinearity of the palms
6
Q

Irritant Contact Dermatitis - Definition

A

Non-immunologically mediated reaction resulting from direct cytotoxic effect caused by a chemical irritant

7
Q

Intertrigo

A

Rashes of the skin folds caused by trapped sweat and exacerbated by friction

Treated with mild topical corticosteroid, i.e. Hydrocortisone

Secondary infection with yeast is common

8
Q

Allergic Contact Dermatitis - Definition

A

Type IV, delayed-type hypersensitivity reaction to contact allergen; immune response involves presentation of the antigen by Langerhans cells in the skin and development of memory T cells which release inflammatory cytokines TNF-a and IL-1

Diagnosed by patch test

9
Q

Stasis Dermatitis - Associated Features

A

Other signs of venous insufficiency of the lower extremitie:

Varicose veins
Chronic lower extremity edema
Venous Stasis Ulcers

10
Q

Stasis Dermatitis - Clinical Presentation

A

Dryness
Itching
Lichen Simplex Chronicus
Secondary allergic contact dermatitis due to use of topic agents
Secondary irritant contact dermatitis due to accumulation of purulent material from ulcers

11
Q

Lichen Simplex Chronicus

A

Thick, scaly plaques that result from chronic rubbing and scratching

12
Q

Venous Stasis Ulcers

A

Primarily found on the medial lower leg just before the ankle; red with yellow, fibrinous base & irregularly shaped borders

13
Q

Nummular Dermatitis

A

AKA Discoid Eczema; characterized by red, scaly, crusty patches appearing most often on the legs, sometimes on arms and trunk

Treatment: moisturization & topical corticosteroids

14
Q

Seborrheic Dermatitis

A

Flaky, white/yellow, oily scale occurring in areas rich in sebaceous glands (scalp, face, ears, chest)

In children, usually presents on the scalp as “cradle cap”

In adults, often presents as symmetric involvement over the face over medial eyebrows, nasolabial folds, and ears; also presents on the scalp as “Dandruff”

15
Q

Seborrheic Dermatitis - Pathogenesis

A

Over-production of skin oil and irritation from Malassezia furfur yeast

16
Q

Dandruff

A

Seborrheic Dermatitis of the scalp

Differentiated from psoriasis by more diffuse lesions and finer scale

17
Q

Psoriasis - Comorbidities

A

Persistent, low grade, systemic inflammation; risk factor for development of insulin resistance, obesity, metabolic syndrome, and cardiovascular disease

5-20% of patients will develop psoriatic arthritis

18
Q

Psoriasis - Clinical Subtypes

A
Chronic Plaque Disease
Guttate 
Erythroderma
Pustular Psoriasis 
Palmar/Plantar Psoriasis
19
Q

Treatment for local Psoriasis

A
Localized Disease: 
Calcipotriol (Vitamin D3 analog)
Corticosteroids
Topical Retinoids
Phototherapy
20
Q

Treatment for systemic Psoriasis

A

Systemic Disease:
Methotrexate
Cyclosporin
Biologics - anti-T lymphocytes, anti-TNF alpha

21
Q

Atopic Dermatitis - Common Locations

A

Characteristic involvement of flexural skin:

Antecubital fossa
Popliteal Fossa
Neck
Wrists
Ankles
22
Q

Psoriasis - Common locations

A

Characteristic involvement of extensor surfaces

23
Q

Vitamin D synthesis

A

7-dehydrocholesterol in epidermal keratinocytes can be converted by UVB to Vitamin D3; Vitamin D3 is then converted to 25-hydroxy Vitamin D by the liver; 25-hydroxy Vitamin D is converted in to the kidney to the active form, 1,25-dihydroxy Vitamin D (Calcitriol)

24
Q

Melanocytes

A

Pigment producing cells of the epidermis; protects DNA from UV damage

Located in the basal layer of the epidermis, within hair follicles; found in a 1:10 ratio of melanocytes: keratinocytes

Produce melanin packaged in granules called melanosomes, each melanocyte supplies melanin to 30 nearby keratinocytes

25
Q

Langerhans cells

A

Dendritic cells of the epidermis, found in small numbers in all of the epidermal layers

Circulate between the skin & lymph node where they present antigens to the immune system

26
Q

Stratum Corneum

A

Outermost layer of epidermis

Made up of dead keratinocytes that have lost their nuclei and organelles

27
Q

Filaggrin - Normal function & Mutation

A

Breakdown of filaggrin forms Natural Moisturizing Factor (NMF) which binds H20 to keep the skin moist

Patients with filaggrin mutations have reduced levels of NMF in the stratum corneum, leading to icthyosis vulgaris and atopic dermatitis

28
Q

Stratum Lucidum

A

Thin layer of anuclear cells without organelles, seen only in the thick skin between the stratum corneum and stratum granulosum; reduces shear forces between these two layers

29
Q

Stratum granulosum

A

Cells in this layer start to lose their nuclei as they migrate toward the epidermal surface; these cells contain keratohyalin granules full of profilaggrin (filaggrin precursor)

30
Q

Stratum Spinosum

A

Thickest layer of the epidermis; functions to protect against mechanical injury, UV, pathogens, and chemicals

31
Q

Desmosomes

A

Specialized adherence proteins that enable cell-cell adhesion between keratinocytes in the epidermis

32
Q

Pemphigus Vulgaris

A

Caused by acquired antibodies to desmosomes in the epidermis

Presents as flaccid intraepidermal blisters in the skin and mucous membranes

33
Q

Stratum Basalis (Germinativum)

A

Inner most layer of the epidermis (basal cell layer); consists of a single layer of columnar or cuboidal keratinocytes - these are the stem cells of the epidermis

34
Q

Hemidesmosomes

A

Specialized adherence proteins that function in the attachment of basal cells of the epidermis to the basal lamina of the dermal epidermal junction

35
Q

Bullous Pemphigoid

A

Most common autoimmune bullous disorder; caused by the production of auto-antibodies to hemidesmosomes at the dermal-epidermal junction

Diagnosed by direct immunofluorescence
Treated with oral steroids or Rituximab

36
Q

Papillary Layer of the Dermis

A

Top layer of the dermis, directly underlying the epidermis; forms the dermal component of the dermal-epidermal junction; consists of loose connective tissue rich with capillaries that are the blood supply for the epidermis

37
Q

Meissner’s Corpuscles

A

“Pine cone”-like structure, consists of Schwann cells and sensory nerve terminals wrapped by fibroblasts and collagen; most often found in the dermal papillae of thick skin

Sensitive for detection of delicate touch

38
Q

Reticular layer of the Dermis

A

Lies deep to the papillary layer; contains extensive collagen and elastic fibers lending strength & flexibility

Houses glands, hairs, and major blood vessels that facilitate thermoregulation

39
Q

Pacinian Corpuscles

A

“Onion-like” structures; consist of a single sensory nerve terminating within a concentric layer of connective tissue; found in the dermis of thick and thin skin

Detects vibration

40
Q

Apocrine glands

A

Produce a milky, viscous, carbohydrate-rich secretion; secretion is initially odorless but subsequent bacterial action leads to characteristic body odor

Located in axillary, pubic, and perianal regions

41
Q

Eccrine Glands

A

Traditional sweat glands distributed over most of the body; secrete watery, electrolyte, enzyme-rich secretion that is initially isotonic but becomes hypotonic as Na+ is reabsorbed by the ducts; important for thermoregulation

Not found on lips, under finger/toe nails, on the glans of the penis/clitoris, or on the labia minora

42
Q

Arrector pili

A

Smooth muscle structure that causes hair to “stand on end”

43
Q

Sebaceous glands

A

Secrete sebum, a complex mixture of lipids; develop along with hair follicles & empty their secretions into the upper 1/3 of the follicle

Sex hormones are required to secrete sebum, which functions to lubricate and moisturize the skin

44
Q

Types of Pigment (2)

A

Eumelanin - Black to brown pigment

Pheomelanin - Yellow to red-brown pigment

45
Q

Distribution of Melanosomes - Light vs. Dark skin

A

Light skin: Melanosomes are distributed in clusters above the keratinocyte nucleus

Dark skin: Melanosomes are larger and distributed individually throughout the cytoplasm of the keratinocytes

46
Q

Vitiligo

A

Acquired depigmentation due to absence of melanocytes in affected areas of skin

Most often affects the mouth, eyes, and fingertips

47
Q

Macule vs. Patch

A

Circumscribed change in skin color that is flush with surrounding skin

Macules are < 1 cm
Patches are > 1 cm

48
Q

Papule vs. Nodule vs. Tumor

A

Solid or cystic elevation of the skin

Papules are < 1cm
Nodules are between 1 and 2 cm
Tumors are > 2 cm

49
Q

Plaque

A

An elevated skin lesion > 1 cm

50
Q

Scale

A

Desiccated, thin plates of epidermal cells that form flakes on the skin surface

51
Q

Wheal

A

Circumscribed, flat-topped, firm elevation of skin with a well demarcated and palpable margin

i.e. Hives

52
Q

Vessicle vs. Bulla

A

Circumscribed, elevated lesion containing clear serous or hemorrhagic fluid

Vessicles are < 1 cm
Bulla are > 2 cm

53
Q

Pustule

A

A vesicle containing purulent exudate

54
Q

Atrophy vs. Erosion vs. Ulceration

A

Atrophy - a depression on the surface of the skin with loss of underlying epidermal or dermal substance

Erosion - a depression on the surface of the skin with loss of all or part of the epidermis

Ulceration - a depression on the surface of the skin with loss of the entire epidermis and some of the dermis

55
Q

Telangiectasias

A

Visible, persistent dialation of small, superficial capillaries

56
Q

Eschar

A

A thick, dry, crusty scab - usually black in color

57
Q

Lichenification

A

Dry, leathery thickening of the skin with exaggerated skin markings

58
Q

Dermal Matrix

A

A mixture of collagen, elastin, and ground substance

Ground substance is mostly comprised of GAGs; these molecules are highly hydrated, allowing for diffusion of nutrients from the dermis into the epidermis

59
Q

Ehlers-Danlos Syndrome (EDS)

A

Congenital disorder of collagen synthesis, leading to the production of abnormal collagen

Causes skin hyperextensibility, joint hypermobility, tissue fragility, and poor wound healing

60
Q

Solar Elastosis

A

Accumulation of sunlight exposure leads to degeneration of elastin fibers; fibers become dystrophic and tend to clump

61
Q

Pseudoxanthoma Elasticum (PXE)

A

Caused by a mutation in a gene encoding for the MDR efflux pump; this mutation also causes elastic fibers of the dermis to become tangled and calcified

Skin of flexural areas develops a “plucked chicken” look

Elastic fibers of blood vessels are also damaged, leading to hypertension and bleeding disorders

62
Q

Leukocytoclastic Vasculitis

A

Caused by precipitation of immune complexes in the walls of post-capillary venules, secondary to drug hypersensitivity, infection, etc.

Leads to inflammation, degranulation of neutrophils causing vessel wall damage, and extravasation of RBCs into the dermis

Manifests as palpable, non-blanchable purpura

63
Q

Hair follicles - structural elements

A

Divided into into metrical area (lower 1/3), isthmus (middle 1/3), and infundibulum (upper 1/3)

Also comprised of lower bulge (attachment for arrector pili), middle bulge (sebaceous gland), and upper bulge (apocrine gland)

64
Q

Terminal vs. Vellus Hairs

A

Terminal hairs - large, thick, and coarsely pigmented; present on the scalp, beard, and pubic area

Vellus hairs - small, fine, and apigmented; located diffusely on the body

65
Q

Acne

A

Acquired disorder of the pilosebaceous unit caused by plugging of the follicle by hyperkeratotic debris leading to the accumulation of oil; normal bacterial commensals multiply within the follicle and convert sebum to pro-inflammatory fatty acids

66
Q

Anhidronic Ectodermal Dysplasia

A

Aberrant eccrine gland formation; patients do not sweat, leading to problems with thermoregulation

67
Q

Chromhidrosis

A

Disorder of apocrine glands, characterized by the presence of lipofuscin pigment that colors apocrine sweat yellow/green/blue/black in various oxidative states

68
Q

Cherry angioma

A

Most common vascular tumor in adults; primary lesion is a bright red, smooth topped papule

Can be treated with electrodessication, liquid nitrogen, or shave biopsy

69
Q

Infantile hemangioma

A

A benign endothelial cell neoplasm - the most common soft tissue tumor of infancy

Often a precursor lesion is noted at birth followed by rapid proliferation in the first 1-3 months

Complications: Peri-ocular lesions may interrupt vision, lip lesions prone to ulceration

Many cases resolve spontaneously by age 5; persistent cases treated with beta blockers (propanolol), steroids, or laser

70
Q

Port Wine Stain

A

A vascular malformation that is present at birth and persists into adulthood; caused by somatic mutation GNAQ

Complications: Varicose veins, venous stasis, edema, ulceration

71
Q

Sturge-Weber Syndrome

A

Associated with port wine stain, ocular and neurologic abnormalities including glaucoma, seizures, and developmental delay

72
Q

Sebaceous Hyperplasia

A

Benign tumor of the oil gland often located on the face, trunk, and extremities

Primary lesion is a 1-6mm yellowish-white papule

Treatment is for cosmetic reasons only by electrodessication or cryotherapy

73
Q

Nevus sebaceous

A

A papillomatous, yellow-orange, linear plaque on the face or scalp; lesions on the scalp are associated with alopecia

Rapid growth may occur during puberty with enlargement of sebaceous glands and epidermal hyperplasia

Can be treated with surgical excision

74
Q

Acrochordon

A

Aka “Skin Tag”

Soft, flesh-colored papules with a narrow base

Complications: Recurrent trauma, torsion

Treatment: Snip excision, cryotherapy, electrodessication

75
Q

Lipoma

A

Benign tumor of adipose tissue - the most common form of soft tissue tumor

Usually soft to the touch, movable, and painless

76
Q

Dermatofibroma

A

Primary lesion is a firm, round nodule

May be depressed or dome-shaped, rarely larger than 1cm; color is tan or brown and dimples when squeezed

Generally solitary distribution over the legs

77
Q

Keloid

A

A raised scar that extends beyond the borders of the original wound; results from an overgrowth of granulation tissue at the site of a healed skin injury

Generally present as firm, rubbery lesions or shiny nodules; can vary in color from pink to red to dark brown

78
Q

Seborrheic Keratosis

A

Benign tumors of the hair follicle typically found on the head, neck, and trunk

Primary lesion is a brown papule with a “stuck on” appearance; may be smooth or slightly raised, often studded with small pits

Treatment: Cryotherapy

79
Q

Clinical subtypes of Seborrheic Keratosis

A

Dermatosis Papulosa Nigra
Stucco Keratosis
Inflamed Seborrheic Keratosis
Sign of Leser-Trelat

80
Q

Nevocellular Nevi

A

“Moles”

Age of onset from infancy to childhood; distributed over any skin surface including mucous membranes; increased on sun-exposed skin

May be intradermal, junctional, or compound

81
Q

Congenital Nevi

A

Caused by melanocytes that migrate from the neural crest and remain inappropriately within the dermis and do not progress into the epidermis

Giant congenital nevi are associated with a slight increased risk for melanoma

82
Q

Familial Atypical Mole and Melanoma (FAMM) Syndrome

A

Diagnosis requires:

The occurrence of malignant melanoma in 1 or more first or second degree relatives

Presence of many (>50) nevi, some of which are clinically atypical

Risk of melanoma approaches 100%

83
Q

Neurofibromatosis

A

Autosomal dominant mutation of the neurofibromin (NF-1) gene, a tumor suppressor; exhibits variable expression & pleiotropy

Signs include: 
Cafe au lait spots 
Neurofibromas
Axillary freckling
Lisch nodules
84
Q

Basal Cell Carcinoma (BCC)

A

Most commonly diagnosed malignancy in the US

Rarely fatal but can become invasive, causing complications that involve the eye or brain

Originates from keratinocytes

85
Q

Moh’s surgery

A

Tissue-sparing tumor removal technique, indicated for tumors that are located in cosmetically sensitive areas, large in size, or recurrent

86
Q

Clinical subtypes of BCC

A

Superficial
Nodular (75%)
Infiltrative
Sclerosing/Morpheaform

87
Q

Risk factors for Basal Cell carcinoma

A

Fair skin

UV exposure

88
Q

Risk factors for Squamous Cell Carcinoma

A
UV damage 
Thermal injury
Radiation
HPV
Chronic injury / inflammation 
Immunosuppression
89
Q

Squamous Cell carcinoma

A

Hyperkeratotic papule of variable size and thickness, typically found on chronically sun damaged skin

Metastasis occurs in .5-5% but is more common in SCC of the lip (10-30%)

90
Q

Clinical subtypes of SCC

A

SCC In Situ - Full thickness atypia of the epidermis; does not involve the dermis

Keratoacanthoma - rapidly growing, volcano-like nodule with central crater

Invasive SCC

91
Q

Melanoma Risk Factors

A
Fair skin 
Sun exposure 
Age 
Immunosuppression 
MM in first degree relative 
Large congenital nevus 
FAMM
92
Q

Clinical subtypes of Melanoma

A

Superficial spreading
Nodular
Lentigo Maligna Melanoma
Acral Lentiginous

93
Q

Actinic Keratosis

A

AKA Intraepidermal neoplasia

The most common pre-cancerous lesion: 65% of all SCCs and 36% of all BCCs arise in lesions that were previously diagnosed as AKs

Treatment:
Cryotherapy
Topical agents - chemotherapies, immunotherapies, NSAIDs
Phototherapy

94
Q

Major mutation in BCC + Specific Therapy

A

The majority of BCCs have a loss of function in the PTCH1 gene, which normally acts to block smoothened (SMO), an oncogene involved in tumor signaling

Vismodegib is an inhibitor of smoothened, approved for targeted treatment of advanced BCC

95
Q

Common mutation in Melanoma + Targeted Therapy

A

50% of melanomas have a mutation in the BRAF gene

Treatment: Vemurafenib, a BRAF inhibitor

96
Q

Clark’s Levels

A

I. Epidermis
II. Papillary Dermis
III. Mid Dermis
IV. Reticular Dermis

97
Q

Breslow Depth

A

Tumor invasion measured in millimeters

Tumor biopsy is indicated for patients with tumor invasion > 1 mm

98
Q

Solar spectrum & Sunburn

A

UVB is the shortest wavelength (highest energy) and is responsible for more severe sunburns; UVA is somewhat lower energy and is associated with use in tanning beds to cause tanning without burning

99
Q

Why do sunburns peel?

A

Peeling is evidence of p53 activation of apoptosis in DNA damaged keratinocytes; these cells slough off as they die and are replaced by new cells from the basal layer

100
Q

Defenses against reactive oxygen in the epidermis

A

Peroxidases and Catalases - detoxify H2O2 to H2O and O2

Superoxide dysmutase - detoxify superoxide anion to H2O2

Glutathione reductase

Thioredoxin reductase - reduces disulfide bonds

101
Q

Mechanism of melanosome biosynthesis

A

Melanosome precursor vesicles from the smooth ER fuse with tyrosinase-containing vesicles from the Golgi that important for production of melanin; fully mature melanosomes transit down the dendrites of the melanocyte and are extruded into surrounding keratinocytes

102
Q

How does UV damage stimulate melanin content in the skin?

A

UV radiation stimulates a number of cell signaling pathways, including p53; activation of p53 leads to production of signaling intermediates that are secreted from the damaged keratinocyte and activate receptors on the melanocyte that signal the cell to up-regulate melanogenesis; melanosomes are transported down the axons of the melanocytes and deposited into the keratinocyte

103
Q

Types of DNA damage produced by UVR

A

Thymine Dimers - induced by UVB
Pyrimidine-6-4-pyrimidone - induced by UVB
Hydroxyguanosine - induced by UVA

104
Q

Defense Mechanisms of the skin

A

Physical barrier
Desquamation
Localized immune response - Langerhans Cells, Immunoglobulins
Anti-microbial peptides - alpha defensins
pH

105
Q

Warts - Virus & Types

A

Caused by HPV

Veruca Vulgaris
Veruca Plantar - commonly seen on the plantar surface of the foot
Verruca Plana - commonly spread by shaving

106
Q

Herpetic Whitlow / Herpes Progenitalis

A

HSV-1 presenting on the finger tips (Herpetic Whitlow) or genitals (Herpes Progenitalis)

Presents as grouped blisters on a red base; often preceeded by “tingling” prodrome, often recurrent

107
Q

Streptococcal Non-bullous Impetigo (Impetigo Contagiosa)

A

Common superficial infection of the face in children

Primary lesion is a plaque with “honey colored” crust

Most common complication (5%) is acute post-streptococcal glomerulonephritis

108
Q

Staphylococcal Non-Bullous Impetigo

A

Most commonly affects the face of adults, frequently secondary to injury or dermatitis due to self-inoculation with Staph flora from the naris

Primary lesion is a plaque with “honey crust” over the surface;

109
Q

Cellulitis

A

Staphylococcal or Streptococcal

Ill-defined area of erythema on the body (not face)

Lymphatic streaking and lymphadenopathy are common; may lead to sepsis

110
Q

Eryiseplas

A

Facial cellulitis variant, may be Staphylococcal or Streptococcal

Bright red, bilateral erythema and swelling of the face with well-demarcated “cliff drop” border

111
Q

Syphilis

A

Caused by treponema pallidum spirochete

Primary - painless chancre at site of infection

Secondary - presentation varies greatly but classic presentation is non-pruritic, papulosquamous lesions on the palms and soles; lymphadenopathy in 90%

Diagnosed by biopsy or serology, never culture

112
Q

Dermatophyte

A

Fungi that eat keratin on the surface of skin, hair, and nails; cause superinfection only

Epidermophyton - “Socks and Jocks”
Trichophyton
Microsporum

113
Q

Tinea Capitis

A

Grey patch variant - Grey patch with associated hair loss; often associated with occipital lymphadenopathy

Black dot variant

May present as a Kerion - inflammated, scaly lesion

114
Q

Tinea - faciei, barbae, corporis, cruris, pedis, manum

A

Classic presentation is annular plaque with raised border and central clearing

Tinea faciei - presents on the face of children

Tinea barbae - presents on the bearded face in men

Tinea corporis - presents on the body; “ring worm”

Tinea cruris - presents on the groin area

Tinea pedis - presents on the feet, usually bilaterally; may present as hyperkeratotic variant

Tinea manum - presents on the hand, often unilaterally

115
Q

Majocchi’s Granuloma

A

Deeper fungal infection of the hair follicle, occurs secondary to superficial dermatophyte infection

116
Q

Candidiasis - 3 presentations

A

Candida fungus uses glucose as a food source; often causes deeper infection

Thrush - fungal plaque infection of oral mucosa

Perleche - chronic infection at the edges of the mouth

Diaper dermatitis - beefy red rash with satellite pustules

117
Q

Scabies

A

Caused by Sarcoptes scabiei mites

Classic presentation is pruritic, erythematous papules and burrows distributed symmetrically over the interdigital web spaces, flexural wrist, waistband, axilla, and groin

Diagnosed by skin scraping or biopsy

118
Q

Lice - 3 varieties

A

Pediculus humanus var. capitis - head lice

Pediculus humanus var. corporis - body lice; presents as truncal, erythematous papules and macules; louse found on clothing only

Phthirus pubis - Crab louse; presents with pruritis of genital area; crabs are easily found attached to the base of hair follicles

119
Q

Clubbing

A

Enlargement of the soft tissue of the distal digit with excessive curving of the nail plate

Associated with :
GI disease - Crohn’s, Ulcerative Colitis
Malignancy - Thyroid cancer, Hodgkin Disease
Pulmonary or Cardiac disease causing hypoxia

120
Q

Kaposi’s Sarcoma (3 types)

A

Slowly progressive endothelial malignancy triggered by HHV-8; 3 types:

  1. Classic - primarily in elderly men of Eastern European descent; presents in the lower leg
  2. Lymphadenopathic - aggressive form primarily affecting young men in equatorial Africa
  3. AIDS-associated
121
Q

Alopecia Areata - Systemic associations

A

3 presentations:

  1. Non-scarring alopecia occurring as round patches of hair loss
  2. Alopecia totalis - total scalp hair loss
  3. Alopecia univeralis - total body hair loss

Often associated with auto-immune disease including thyroid disease, vitiligo, and irritable bowel syndrome

122
Q

Vitiligo - Systemic associations

A

Commonly associated with thyroid disease (Hashimoto’s, Graves), and other endocrine disorders

123
Q

Erythema Nodosum - Systemic associations

A

Deep inflammation of the subcutaneous fat (panniculitis); presents as painful, erythematous subcutaneous nodules usually symmetrically over the pretibial lower extremity

Considered a delayed type hypersensitivity reaction to antigenic stimuli, most commonly infection; often associated with streptococcal infections, especially URI

124
Q

Pyoderma Gangrenosum - Systemic associations

A

Lesion usually begins as a pustule on an erythematous base and evolves into an ulcer with a necrotic border; often begins at sites of minor trauma

Associated with:

Inflammatory Bowel Disease
Arthritis
Hematological Disorder

125
Q

Lichen planus - Systemic associations

A

Purple, polygonal, pruritic papules with Wickam’s striae (overlying pattern of white lines on the surface)

Associated with Hepatitis C

Oral LP associated with contact allergy to dental metals

126
Q

Acanthosis Nigricans - Systemic associations

A

Velvety hyperpigmentation of intertriginous surfaces, especially neck and axilla; caused by factors stimulating epidermal keratinocyte proliferation

Associated with obesity, Diabetes, and other endocrinopathies

Also associated with malignancy - adenocarcinoma of stomach; often with rapid onset of the skin condition as well as rapid weight loss

127
Q

Urticaria - Systemic associations

A

Immediate type I (IgE-mediated) hypersensitivity reactions; may be acute or chronic

Acute - <6 weeks; often associated with infection, drugs, and food

Chronic - development of auto-antibodies to self Fc receptors

128
Q

Drug eruptions

A

Typically eczematous drug eruptions; delayed type hypersensitivity reaction, usually with onset within 7-14 days of starting a new medication

Treated with topical steroids and systemic anti-histamines

129
Q

Stevens-Johnson Syndrome

A

Drug eruption caused by immune complex-mediated hypersensitivity; characterized by a rash that begins on the face and upper trunk and evolves to skin necrosis and flaccid bullae involving mucous membranes; detachment of epidermis often results

SJS involve < 10% of body surface
Toxic Epidermal Necrolysis involves > 30% body surface

130
Q

Type A nerves

A

Heavily myelinated, fast conducting nerve fibers

Convey localized pain

131
Q

Type C nerves

A

Unmyelinated, slow-conducting nerve fibers

Convey sensation of diffuse, dull, non-localizing itching and temperature

132
Q

Hair Cycle

A

Hairs are randomly engaged in 1 of 3 cycles

Anagen - Growth Phase
Telogen - Rest Phase
Catagen - Involution Phase

133
Q

Male Pattern Baldness - Causes & Treatment

A

Caused by conversion of testosterone to DHT

Treated by Propecia: selective inhibitor of 5-a-reductase, which prevents this conversion