Derm Intro and Common Dermatoses I and II Flashcards Preview

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Flashcards in Derm Intro and Common Dermatoses I and II Deck (83)

Three main ways to describe/characterize skin lesions

(1) Morphology of the primary lesion
-elevated, flat, depressed
-secondary characteristics

(2) Configuration

(3) Distribution


Differentiate primary and secondary lesions

Primary lesions = what came first

-secondary lesions = a process that happens to the primary lesion
ex: scabbing, inflammation, scale, crust, scar, erode, ulcer


Name the primary lesion:

Flat less than 1 cm

Macule = flat lesion


Name the primary lesion:

Flat > 1 cm

Patch = flat lesion > 1 cm


Name the primary lesion:

Raised less than 1 cm

Papule = raised


Name the primary lesion:

Raised > 1 cm

Plaque = raised > 1 cm

(think plaques are raised off the wall)


Name the primary lesion:

Blister less than 1 cm

Vesicles = blisters


Name the primary lesion:

Blister > 1 cm

Bullae = blisters > 1 cm


Define acral

= type of distribution on the hands and feet


Define koebnerizing

= skin lesions appearing on lines of trauma

-can be spread in linear patterns by self-scratching


Where is the lesion in a macule?

Macule = flat lesion less than 1 cm
-lesion is superficial: in the epidermis or superficial dermis


Where is the lesion in a patch?

Patch = flat lesion > 1 cm
-non palpable
-lesion is superficial: in the epidermis or superficial dermis


Mechanism of a papule and plaque lesions

Papule = palpable, elevated lesion less than 1 cm

-proliferation of cells in the epidermis or superficial dermis


Define pustule

(a) Location

Pustule = superficial elevated lesion w/ yellow or white fluid (pus)

pus = protein rich, contains neutrophils

(a) w/in or just beneath the epidermis

ex: acne, fungal infection


Differentiate vesicle and pustule

Vesicles contain clear fluid, while pustules contain pus (yellow or white fluid)


Define nodule

Nodule = palpable, firm

-proliferation of cells in the mid-deep dermis or subcutis


Differentiate nodules and plaques

Nodules are deeper than papules/plaques


Define scale

= masses of keratin
-due to rapid proliferation of epidermal cells => the pathology is in the epidermis (not the dermis or subcutaneous tissue)


Define verrucose

Covered in warts/warty


Differentiate scale and crust

Scale = when skin is proliferating quickly


Crust = when something dries on top of something else


Define crust

= dried serum, pus, or blood
-can be mixed w/ epithelial and/or bacterial debris
ex: scab is a crust


'Honey colored crusts'

Honey colored crusts = impetigo


What kind of process won't scar?

Scar is CT replacing lost substance in the dermis or deeper => a process in the epidermis won't scar


Will an erosion scar?

Erosion = loss of all or part of the epidermis

Will heal w/o scaring (b/c scaring is replacing lost substance in dermis or deeper- not epidermis)

-may occur from vesicles or bullae
-may form crusts


Will an ulcer scar?

Ulcer = complete loss of epidermis and part of dermis

-usually heals w/ scarring (b/c is deeper than the epidermis)


Differentiate a fissure from

(a) an erosion
(b) an ulcer

Fissure = linear or wedge shape tear in the epidermis
(like in winter and the edges of your mouth crack)

(a) Erosions are wider than fissures, but both erosions and fissures are of the epidermis
-differ by shape and size, not depth

(b) Ulcers are deeper than fissures- ulcers involve the dermis


Define atrophy of skin

(a) Appearance
(b) Texture

Atrophy = thinning or depression of skin due to reduction in underlying tissue
-clinical chance due to a decrease in the dermal CT and/or epidermis

(a) Skin appears thin, smooth, finely wrinked, possible telangiectasias.
(b) Feels soft and dry


What are excoriations?

= Superficial abrasions in the skin produced by mechanical means, usually by scratching

-usually only involves the epidermis, but can sometimes involve the upper dermis


Define lichenification

= thickening of skin associated w/ increased lines and skin markings
-chronic rubbing/scratching => hyperkeratosis

-due to chronic scratching, associated w/ eczema


What are some words to describe the configuration of skin findings?

-annular (ring like)
-serpigenous (snake like)


What would be the next step in a workup for someone w/ a ton of warts?

Warts = HPV infections
-increased infection in immunocompromised pts => if someone has a ton of warts test for HIV

-would be abnormal to have someone w/ a healthy immune system who has a ton of warts


Why do you have to keep an eye on warts?

B/c certain HPV serotypes can be associated w/ squamous cell carcinoma


Define condyloma

(a) Causes

Condyloma = infection of the genitals, 2 subtypes

(i) Condylma acuminata = genital warts, caused by HPV
(ii) Condyloma lata = white lesions caused by secondary syphilis


What might be a visual indication that a wart is active?

(a) And what does it mean that it's active...?

Little black dots on the wart are blood vessels, indicate that the wart is active

(a) An active wart can be frozen but will just come back


Mechanism of wart infection

HPV virus infects the basal epithelial cells and induces hyperproliferation


How are warts spread?

Skin to skin contact
-or genital contact (gross)


Describe the 2 approaches to treating warts

(a) Caustic agents or surgical/chemical destruction

(b) Immunotherapy, ex: candida antigen

(c) 2 ways to prevent genital warts

Treating warts

(a) Caustic agents to destroy the epidermis where the wart in living
ex: salicyclic acid, cryo (freezing), laser, blister beetle, topical 5-FU

(b) Trick the immune system into attacking the wart
ex: inject candida antigen into the base of the wart- immune system recognizes the candida and attacks the wart

(c) Prevent genital warts w/ condoms and Guardisil vaccine


Describe the characteristic psoriatic lesion

Psoriasis- bright red plaque w/ a sharply defined border and silvery white scale


What are the characteristic sites for psoriasis?

Elbows, knees, scalp, lumbosacral region


What physical exam finding in psoriasis is correlated w/ increased risk of psoriatic arthritis

Nail involvement

-nail involvement in up to 40% o psoriasis cases
ex: pitting, oil droplet discoloration, onycholysis


Besides arthritis, what does psoriasis increased risk for?

Cardiac disease
ex: arrhythmias


Distinguish the classic locations for psoriasis vs. eczema

Psoriasis typically on extensor surfaces (like back of the elbow), while eczema is typically on flexor surfaces


Give some examples of intertrigenous areas

Intertrigenous areas = where two skin areas touch or rub

ex: under boob, armpit, groin


Treating psoriasis

(a) Topical
(b) Light therapy
(c) Systemic options
(d) Immunotherapy

Treating psoriasis

(a) Topical = corticosteroids, vitamin D analoges
(b) Light therapy: UVB light, unclear mechanism
(c) Systemic: methotrexate and retinoids
(d) Anti-TNFalpha monoclonal antibody = Remicade


Describe the diseases mechanism of psoriasis

Immunologic factors (both polygenetic and environmental) induce epidermal hyperproliferation (by shortening the cell cycle)

-systemic immunologic disease => increased cardiac and arthritis risk

-presence of activated T cells and excess neutrophils in lesions


What is a critical proinflammatory cytokine in psoriasis


(hence why Remicade is so beneficial in treatment)


Describe the disease mechanism of tinea versicolor

Tinea versicolor = chronic, asymptomatic, superficial fungal infection caused by the yeast malassezia furfur

-yeast is in the outermost layer of the skin = stratum corneum


What does a KOH prep test for?

The yeast malassezia furfur = causes tinea versicolor

-see 'spaghetti and meatball' appearance of the both hyphae and spores of the years in the stratum corneum or scale of lesion


What is the most common cause of dandruff?

= Seborrheic dermatitis = irritated, oily scalp due to inflammatory desquamative reaction in oil rich areas


Disease mechanism of seborrheic dermatitis

(a) describe the scale

=inflammatory desequamative rxn in oil rich areas (face, scalp, ears)
-increased sebum production

(a) scale often yellow and greasy


What disease is found most commonly in the glabella and nasolabial folds?

Seborrheic dermatitis

-glabella = skin btwn eyebrows above nose


Seborrheic dermatitis treatment

(a) Scalp
(b) Face

Treating seborrheic dermatitis

(a) scalp = azole shampoo or cream
-OTC anti-dandruff shampoos

(b) Face = combo of topical antifungal and hydrocortisone


Distinguish blackheads and whiteheads

Comedones = plug of sebum and keratin in the sebaceous gland

blackheads = open comedones

whiteheads = closed comedones


Acne treatment

(a) Topical
(b) Systemic

Treating acne

(a) Topical - often a combo of topical antibacterial, abx, and retinoids
-topical antibacterial = benzoyl peroxide
-retinoids help against the hyperkeratinosis process that clogs pores

(b) Systemic = Accutane (= Isotretinoin, for scaring acne), OCPs or spironolactone (testosterone inhibitor) for hormonal acne
-no longer use oral abx b/c chronic usage => microbiome effects, resistance etc


What does seborrheic refer to?

Greasy appearance and distribution in greasy rich areas (ex: face)


Treatment for seborrheic keratosis

Removal- curretage (scoop up ew), liquid nitrogen, electrodessication


Differentiate tinae versicolor and pityriasis rosea

(a) Staining
(b) Color
(c) Distribution
(d) Other

Tinae versicolor vs. Pityriasis rosea

(a) Tinae versicolor can be diagnosed w/ KOH prep
(b) Tinae versicolor hypo or hyper-pigemented skin color, while pityriasis rosea is red
(c) TV: scattered distribution vs. PR: Christmas tree distribution
(d) PR has a Herald parch


Treatment for pityriasis rosea

No treatment usually needed, just reassurance to the pt that they're ok

-spontaneously resolves (on its own) in 4-6 weeks

-unknown cause => nothing really to treat it faster, can possibly use topical corticosteroids, narrow band UVB


What is a Herald Patch?

= initial lesion of Pityriasis Rosea
-2-6cm annular erythematous patch, then many smaller oval macules come several days later


Disease mechanism of impetigo

Erethematous macules (flat) that develop into fragile vesicles that rupture into an oozing erosion w/ honey colored crusts

-caused by staphylococcus or group A streptococcus

-can be a primary lesion or secondary such as impetigenized acne etc


Differentiate herpes and impetigo

Both have vacuoles but herpes vacuoles are much more regular appearing and impetigo have honey colored crusts


How to treat impetigo

Caused by bacterial infxn (staph or GAS) => bacteriostatic soask, topical abx, or if very severe oral abx


What is the most common cancer in humans?

Basal cell carcinoma
-25% of all cancers diagnosed in the US


Cell of origin of basal cell carcinoma

(a) Environmental risk factor
(b) Risk of metastasis

Malignant neoplasm from nonkeratinizing cells from the basal cell layer of the epidermis

(a) UVB light exposure (sunburn) associated w/ mutation of tsgs
(b) Won't really metastasize, just locally invasive (but still can be very destructive to surrounding tissue


What is the most common clinical type of basal cell carcinoma

Nodular-Ulcterative type = translucent papule (raised


Treatment for basal cell carcinoma

Removal (curettage, electrodessication, surgical) with clear borders


Differentiate the clinical picture of HSV-1 and HSV-2

HSV-1 = non-genital, 'cold sores'

HSV-2 = genital warts


Where does the herpes virus lay dormant?

Neuronal cells in ganglia

-then reactivated by stress, systemic infection etc.


What is a tzank smear?

Bedside smear of an opened herpetic (or other) vesicle, plate for cytologic exam

Herpes findings = intranuclear occlusion and giant cells


How to confirm a diagnosis of herpes?

Tzank smear (bedside cytologic test), viral culture, viral PCR


Treatment for herpes

Avoid triggers and contact with active infection

If treated w/ antivirals early in the flare up (ex: acyclovir, valacyclovir) it can shorten the course of the infection


What is atopic dermatitis?

(a) Associated secondary lesions
(b) Disease mechanism
(c) Associated family history

= Eczema

-chronic eruption of pruritic, erythematous, oozing papules often w/

(a) secondary lichenification (diffuse epidermial thickining) and excoriation (superficial skin abrasions)

(b) Many have defect in flaggrin protein which interferes w/ the skin barrier fxn => increased transepidermial water loss => activation of inflammatory cascade and Th2 response => mast cell and eosinophil activation

(c) Often FHx of allergic rhinitis or astham


Differentiate the distribution of atopic dermatitis in children and adults

Atopic dermatitis (eczema)

Younger children: usually face, extensor surfaces (elbows, knees)

Older children and adults: fossas (anticubital and popliteal), neck, hands, feet


Treatment for atopic dermatitis

1st line: topical steroids, possibly antihistamines to stop the itching (responsible for secondary excoriations)

If very severe => immunosuppression


Define uticaria

Clinical term (many etiologies) of eruption of transient (


Mechanism of uticaria

Hives = release of histamine and other vasopermeable molecules from mast cells


Treatment for uticaria


-if severe (associated w/ anaphylaxis) => epinephrine


Two types of contact dermatitis

80% primary irritant type = contact w/ irritating substance (ex: watch allergy, waist band)

20% allergic type- delayed type IV (cell mediated) hypersensitivity to external allergen (ex: poison ivy, poison oak)


Describe the reaction of contact dermatitis

= inflammation of the skin induced by contact w/ specific allergen which causes edema and erythema usually w/ superimposed vesicles or bullae


What is key to the diagnosis of contact dermatitis


-can often be confused w/ other processes, but the unique and specific distribution (ex: of a sandal, watch, waist band etc) is a give away


Treatment for contact dermatitis

Soaks, topical steroids, antihistamines


What is the most common type of nevi?

(a) Mechanism

Common mole = melanocytic nevus = benign nevus

(a) benign proliferation/accumulation of melanocytes in clusters or nests w/in the epidermis and/or dermis


How to distinguish benign nevus from malignant melanoma


Benign nevus
-symmetric shape
-regular border
-uniform color
-small diameter
-no change