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

Flashcards in Dermatology Deck (133)
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1

Atopic Dermatitis - Diagnosis

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

Atopic Diathesis

Atopic Dermatitis
Asthma
Allergic Rhinitis

3

Atopic Dermatitis - Pathogenesis

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

Atopic Dermatitis - Clinic Presentations by age group

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

Atopic Dermatitis - Associated Features

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

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Irritant Contact Dermatitis - Definition

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

7

Intertrigo

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

Allergic Contact Dermatitis - Definition

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

Stasis Dermatitis - Associated Features

Other signs of venous insufficiency of the lower extremitie:

Varicose veins
Chronic lower extremity edema
Venous Stasis Ulcers

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Stasis Dermatitis - Clinical Presentation

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

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Lichen Simplex Chronicus

Thick, scaly plaques that result from chronic rubbing and scratching

12

Venous Stasis Ulcers

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

13

Nummular Dermatitis

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

Seborrheic Dermatitis

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

Seborrheic Dermatitis - Pathogenesis

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

16

Dandruff

Seborrheic Dermatitis of the scalp

Differentiated from psoriasis by more diffuse lesions and finer scale

17

Psoriasis - Comorbidities

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

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Psoriasis - Clinical Subtypes

Chronic Plaque Disease
Guttate
Erythroderma
Pustular Psoriasis
Palmar/Plantar Psoriasis

19

Treatment for local Psoriasis

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

20

Treatment for systemic Psoriasis

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

21

Atopic Dermatitis - Common Locations

Characteristic involvement of flexural skin:

Antecubital fossa
Popliteal Fossa
Neck
Wrists
Ankles

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Psoriasis - Common locations

Characteristic involvement of extensor surfaces

23

Vitamin D synthesis

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

Melanocytes

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

Langerhans cells

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

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Stratum Corneum

Outermost layer of epidermis

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

27

Filaggrin - Normal function & Mutation

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

Stratum Lucidum

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

Stratum granulosum

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

Stratum Spinosum

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