Dermatitis - Patel Flashcards by Jacob McMillan

describe the appearance of skin in acute dermatitis

vesicular, bullous

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describe the appearance of chronic dermatitis

red, scaly, lichenified with fissures, thickened

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what is a common symptom of all types of dermatits

pruritus

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for allergic contact dermatits (ACD), what is the pathogenesis

delayed type (type IV) T cell mediated hypersensitivity rxn

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for the delayed type HSR seen in ACD, what are the 2 phases?

sensitization (induction) - req 10-14 days and elicitation (challenge) - re-exposure, dermatitis appears w/in 12-48 hours

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what is the most common cause of ACD? what environmental allergens cause this? what is the chemical?

Rhus dermatitis

poison ivy, oak, sumac

urushiol - a resin

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what is the 2nd most common cause of ACD?

nickel (think jewlery) that ain’t a igloo, that’s my watch and that ain’t snow baby thats my chain, that’s not ice girl, that’s my teeth and that’s not a snowcone, that’s my ring

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ACD the main symptom is pruritis, what is the common presentation? appearance of their skin

eczematous, scaly edematous plaques w/ vesiculation distributed in areas of exposure

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what is a key finding in the presentation of Rhus allergy

linear streaks unique distribution tells you it is contact from the external

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what is the appearance of the lesions seen in Rhus allergy?

what do they start off as and what do they become? what forms after 1-2 days?

lesions begin as erythematous macules that become papules or plaques

blisters form over 1-2 days

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treatment of SEVERE Rhus dermatitis? what about duration of this therapy and why?

oral steroids, especially if topical steroids are failing must give for 2-3 weeks - if given for less, pts may relapse

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treatment of normal Rhus dermatitis

minor supportive care - topical steroids, oral or topical antihistamines - to improve pruritis, soothing shit like oatmeal baths and calamine lotion

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what are the characteristics of eyelid allergic contact dermatitis

scaling red plaques on upper eyelids (lower less common) intensely pruritic caused by transfer from hands

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common causes of eyelid allergic contact dermatitis

nail adhesive/polish

fragrances

nickel

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for evaluation of dermatitis, what is a test to identify specific allergens?

patch testing

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since not all pts w/ ACD need patch testing, when should you refer a pt for patch testing

when the allergen is unclear or the dermatitis is chronic

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does a positive reaction of patch testing determine the cause of the pts rash? what confirms the clinical relevance of the positive patch test?

no - positive reaction does not mean the rash is due to that specific allergen

elimination of the rash with removal of the allergen confirms the clinical relevance of the positive patch test

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this obviously dumb, but what is the number 1 treatment of ACD?

avoid exposure to the offending substance (big,bold, could be test question)

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what are the 1st and 2nd most common locations that we talked about for nickel dermatitis?

bridge of nose and around the ears - from glasses

around the umbilicus - from belt buckles erythematous plaque with papules

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what ACD can present with a delayed or immediate type HSR?

latex allergy

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where does the dermatitis usually present for the delayed type of latex allergy

dorsum of hands

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what are some other findings associated with the immediate HSR latex allergy?

disseminated urticaria, allergic rhinitis, and/or anaphylaxis

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what are the two types of contact dermatitis?

allergic and irritant

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define irritant contact dermatitis

ICD - inflammatory rxn in skin resulting from exposure to a substance that can cause an eruption in most people who come in contact with it NON-IMMUNOLOGIC

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is previous exposure necessary in ICD

what is the general mechanism of causation in ICD

**repeated application** from mildly irritating substances (may occur from a single application w/ severely toxic substances, but this is not MC)

what type of disease is ICD? what 2 elements play a role?

multifactorial disease both exogenous (irritant and environmental) and endogenous (host) elements play a role

what is the most important exogneous factor for ICD

the inherent toxicity of the chemical for human skin

what are the most common sites on the body for ICD involvement and why (endogenous elements)

there are site differences in barrier function - skin is thinner face, neck, scrotum, and dorsal hands more susceptible

what is a major risk factor for irritant hand dermatitis

atopic dermatitis impaired barrier function and lower threshold for skin irritation

what are the more common findings in mild ICD

erythema, chapped skin, dryness, and fissuring w/ repeated exposures over time

ICD - what do severe cases present with - clinical findings of skin

edema, exudate, tenderness

what do potent irritants cause in ICD

painful bullae

what is the mainstay of treatment for ICD

identification and avoidance of the potential irritant

when should you perform patch testing with ICD and why

in cases with suspected chronic irritant dermatits (occupational cases) to exclude an allergic contact dermatitis

what is one of the most common skin disorders in developed countries?

atopic dermatitis (AD) 20% of children and 1-3% of adults

what is the definition of atopic dermatitis

AD is a chronic, pruritic, inflammatory skin disease w/ a wide range of severity

what is the primary symptom of AD and what is AD often called

pruritus "the itch that rashes" scratching to relieve AD-associated itch gives rise to the "itch-scratch" cycle and can exacerbate the dz

what is the importance of age in AD?

distribution and morphology of skin lesions varies by age

for AD, what kind of lesions do infants and toddlers develop?

eczematous plaques appear on the cheeks, forehead, scalp and EXTENSOR surfaces

for AD, what type of lesions develop in older children and adolescents?

lichenified, eczematous plaques on FLEXURAL areas of neck, elbows, wrists, ankles

for AD, what type of lesions develop in adults?

Lichenification in flexural regions and involvement of hands, wrists, ankles, feet and face - forehead and around eyes

what is a common characteristic at all stages of AD

Xerosis - dry skin

what type of HSR is atopic dermatits

AD - inflammatory Type I HSR

what is the triad of AD, the "atopic triad"?

AD, allergic rhinitis, bronchial asthma

what is the name of the periorbital findings in AD?

Dennie Morgan folds around the eyes (pleats underneath the eyes)

what is the pathogenesis of AD? what are 4 factors that play a role

multifactorial Genetics, skin barrier dysfunction, impaired immune response, environment

what is a major pre-disposing factor for AD (genetic)

Inherited reduction or loss of the epidermal barrier protein **filaggrin**

what type of immunity does AD favor?

Th2 mediated immunity

what does treatment of AD include (long term use mainly)

long-term use of emollients and gentle skin care - also short term treatment for acute flares

AD - how do you treat the acute inflammation associated with it? (this was one of his key points)

topical steroids

another key point of treatment of AD, what do you do incases of secondary bacterial skin infections

systemic ABX

what is an example of emollients used in treatment of AD

Petrolatum

what is the methodology / reason for using emollients in AD?

they help to compensate/restore the genetically determined impaired epidermal barrier function (he mentioned this twice)

what are 3 types of treatment used for more severe cases of AD?

immunomodulators - topical tacrolimus or pimecrolimus systemic corticosteroids phototherapy - in refractory cases

what is the most common cause (MCC) of infected atopic dermatitis?

Staph aureus

what findings indicate infection in atopic dermatitis

presence of erosions, drainage with yellow crusting

what is Eczema Herpeticum

severe HSV infection in an atopic patient (overlies existing AD)

how does Eczema Herpeticum present

multiple wide spread monomorphic "punched-out" discrete erosions w/ hemorrhagic crusting

what is the treatment of Eczema herpeticum

systemic antivirals - acyclovir severe cases may require hospitalization

what is the presentation of Nummular Dermatitis?

round, coin shaped, light pink, scaly, thin, 1-3 cm plaques

when does nummular dermatitis/ discoid eczema worsen?

during the winter, due to less humidity in the air, increasing skin dryness

where on the body does nummular dermatitis/ discoid eczema develop?

legs, dorsal hands, extensor surfaces, and the trunk

what is the pathogenesis of nummular dermatitis

unknown - may be linked to impaired skin barrier function

what pt population is nummular dermatitis more common in

older individuals

treatment of nummular dermatitis

same as AD or other eczema -corticosteroids, tacrolimus, and emollients however, a number of patients will require phototherapy to clear lesions

what is the pathogenesis of Dyshidrotic Dermatitis (Pompholyx)

course is unknown and NOT related to dysfunction of sweat glands

what is the presentation of Dyshidrotic Dermatitis (Pompholyx)

group of 2-5 mm vesicles, somtimes likened to tapioca pudding

where does Dyshidrotic Dermatitis (Pompholyx) commonly occur?

lateral fingers, central palsm, insteps, lateral borders of feet

what are the symptoms of Dyshidrotic Eczema/ Pompholyx

very pruritic, burning - prickling sensations

what are the associations of Dyshidrotic Eczema/ Pompholyx

Atopic dermatitis and contact dermatitis (allergic and irritant)

define Lichen Simplex Chronicus

Chronic, intensely pruritic skin condition triggered by repeated rubbing and scratching of the skin

what is the presentation of Lichen Simplex Chronicus

solitary, well-defined, pink to tan, thick, and lichenified plaque

what are the common locations of involvement of Lichen Simplex Chronicus

lateral neck, scrotum/vulva, and dorsal foot ----- areas easily accessible by scratching