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Flashcards in Dermatitis - Patel Deck (74):

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



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

delayed type (type IV) T cell mediated hypersensitivity rxn


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


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


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


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


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


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




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

patch testing


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


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


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

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


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


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

latex allergy


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

dorsum of hands


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

disseminated urticaria, allergic rhinitis, and/or anaphylaxis


what are the two types of contact dermatitis?

allergic and irritant


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


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

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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

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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

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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)

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


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



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

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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

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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

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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

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what are the common locations of involvement of Lichen Simplex Chronicus

lateral neck, scrotum/vulva, and dorsal foot


areas easily accessible by scratching