Derm Flashcards
what is the structure and function of the skin?
- barrier against fluid loss
- protection from UV radiation
- thermoregulation
- cushioning
- immunologic protection
- appearance
what is a flat, nonpalpable, <1cm in size lesion called?
macule
what is a flat, nonpalpable, >1cm in size lesion called?
patch
what is a raised, <1cm in size lesion called?
papule
what is a raised, >1cm in size lesion called?
plaque
what is a raised, >1cm in size lesion located in the dermis or subcutaneous fat called?
nodule
what is a fluid-filled, <1cm in size lesion called?
vesicle
what is a fluid-filled, >1cm in size lesion called?
bulla
what is an edematous papule or plaque than lasts < 24 hrs called?
wheal or hive
what is a dry or greasy laminated mass of keratin called?
scale
what is a lesion of dried serum, pus, or blood called?
crust
what is a linear cleft through the epidermis or into the dermis called?
fissure
what is a loss of all or portions of the epidermis alone that heals without scarring called?
erosion
what is a complete loss of the epidermis and some portion of the dermis that heals with scarring called?
ulcer
what is the etiology of nummular “coin-shaped” dermatitis?
- unknown
- classified as a form of atopic derm
at what age(s) is nummular “coin-shaped” dermatitis most common?
- 6th to 7th decade of life w/ M>F
- 2nd to 3rd decade of life F>M
how does nummular “coin-shaped” dermatitis present?
round-to-oval crusted or scaly erythematous plaques
- most common on arms and legs
- start as papules which coalesce into plaques with scale
- early lesions may be studded with vesicles containing serous exudate
- usually very pruritic
- often recurs in the same location as old lesions
- lesions often symmetrically distributed
- waxes and wanes with winter
what are some d/dx of nummular “coin-shaped” dermatitis?
- contact derm
- psoriasis
- CTCL
- pityriasis rosea
- tinea corporis
what is the tx for nummular “coin-shaped” dermatitis?
topical steroids
- may alternate high potency with mid-potency to reduce risk or use on weekends only
topical calcineurin inhibitors (steroid sparing agents)
- tacrolimus (protopic) ointment
- pimecrolimus (elidel) cream
what are some risks of overuse of topical steroids?
- atrophy
- striae
- telangiectasis
- hypopigmentation (temporary)
- can have systemic absorption if using long-term on a large body surface
how should you recommend application of topical steriods to prevent side effects of overuse?
- use <14/28 days
- use 2-3x/week
- Sat/Sun use
on what properties are the 7 classes of topical steroids based?
vasoconstrictive properties
how are the 7 classes of steroids stratified?
- Class 1 = superpotent
- Classes 3 and 4 = mid-strength
- Classes 6 and 7 = low potency
what are some topical steroids that are considered superpotent?
- clobetasol proprionate
- bethamethasone diproprionate
on what body parts are the superpotent steroids best used?
- scalp
- palms
- soles
what are some topical steroids that are considered mid-strength?
- fluocinonide
- betamethasone valerate
- triamcinolone
on what body parts are the mid-strength steroids best used?
- trunk
- extremities
what are some topical steroids that are considered low potency?
- fluocinolone
- desonide
- hydrocortisone
on what body parts are the low potency steroids best used?
- face
- genitals
- intertriginous areas
what are some interventions for nummular “coin-shaped” dermatitis that address hygiene changes and lubrication of skin?
avoid barrier disruption
- harsh soaps
- washcloths
- bathing too frequently
moisturize!
- them more the better
- soak and smear technique - soak in tub of luke warm water for 20 min, pat dry, and liberally apply topical medication or lubricant
what is the etiology of allergic contact dermatitis?
- delayed type of induced sensitivity
- cutaneous contact with a specific allergen to which the patient has developed a specific sensitivity
~25 chemicals are responsible for as many as 1/2 of all cases
what are some common culprits of allergic contact dermatitis?
- poison ivy
- topical abx (neosporin, neomycin, bacitracin)
- nickel
- rubber gloves
- hair dye
- textiles
- preservatives
- fragrances
- benzocaine
how does allergic contact dermatitis present?
pruritic papules and vesicles on an erythematous base
- acute onset
- geometric morphology (circles, lines, etc.)
- lichenified pruritic plaques may indicate chronic ACD
- inital site of dermatitis often provides best clue regarding the potential cause
what are some d/dx of allergic contact dermatitis?
- drug rash
- nummular dermatitis
- seb derm
- tinea
- urticaria
what is the tx for allergic contact dermatitis?
- avoid offending agent
- topical steroids or calcineurin inhibitors
- antihistamines for itching
- cool soaks
- emollients
- oral prednisone in severe cases, but need to tx for 14-21 days
- can refer to patch testing to help determine allergen
when should a drug-induced eruption be considered when evaluating a skin lesion?
in any patient who is taking meds and suddnely develops a symmetric cutaneous eruption (usually occurs w/in 1st 2 wks of tx)
what are some common culprits of drug-induced eruptions?
- antimicrobial agents
- NSAIDs
- cytokines
- chemotherapeutic agents
- anticonvulsants
- psychotropic agents
how do drug-induced eruptions present?
lesions usually appear proximally and generalize w/in 1-2 days
what are some d/dx for drug-induced eruptions?
- contact dermatitis
- erythroderma
- leukocytoclastic vasculitis
- measles
- pityriasis rosea, lichen planus, psoriasis (pustular), urticaria, syphilis
what are the tx for drug-induced eruptions?
d/c offending agent
- can tx w/ antihistamines and topical steroids
- most drug eruptions are mild, self-limited, and usually resolve w/in 2 wks of stopping the offending agent
what are some life threatening drug-induced eruptions?
- SJS
- TEN
what is the most common form of drug-induced eruption?
morbilliform drug rxn
what is the primary lesion(s) of a morbilliform drug rxn?
- macules
- papules
what are the secondary lesion(s) of a morbilliform drug rxn?
none
what is the configuration of a morbilliform drug rxn?
coalescing
what is the distribution of a morbilliform drug rxn?
generalized
what color is a morbilliform drug rxn?
red
what is the etiology of urticaria (hives)?
release of histamines & otherwise vasoactive substances from mast cells and basophils
- 15-20% of general population is affected at some point during their lifetime
- may be acute (lasting < 6 weeks) or chronic (lasting > 6 weeks)
- can occur at any age, but chronic urticaria is more common in 40s and 50s
what are some causes of acute urticaria (hives)?
cause is unknown in > 60% of cases
common causes:
- infections (ask about recent illness and travel)
- caterpillars/moths
- foods (shellfish, nuts)
- drugs (PCN, sulfonamides, salicylates, NSAIDs)
- environmental factors (pollens, plants, danders, dust, mold)
- latex
- exposure to undue skin pressure, cold, heat
- emotional stress, exercise
what are some causes of chronic urticaria (hives)?
cause is unknown in 80-90% of cases
common causes: same causes as in acute urticaria, plus - autoimmune disorders - chronic medical illness - cold urticaria - cryoglobulinemia - syphilis - mastocytosis - inherited autoinflammatory syndromes
how does urticaria present?
blanching, raised, palpable wheals
- occur on any skin area and are usually transient (last < 24 hours) and migratory
- dermatographism may occur (urticaria resulting from light scratching)
with what PE findings should you refer or send to ED?
- angioedema of lips, tongue, or larynx
- urticarial lesions that are painful, long lasting (> 36-48 hrs), ecchymotic, or leave residual hyperpigmentation upon resolution (suggests urticarial vasculitis)
- systemic s/sx: arthralgias, arthritis, weight changes, lymphadenopathy, bone pain
- scleral icterus, hepatic enlargement, or tenderness that suggests hepatitis or cholestatic liver disease
- evidence on skin of bacterial or fungal infection
- listen to lungs for signs of asthma or PNA
what are some d/dx of urticaria?
- contact or atopic dermatitis
- pityriasis rosea
- drug rxn
- mastocytosis
- urticarial vasculitis
what is the tx for urticaria?
H1 antihistamines (benadryl, hydroxyzine, zyrtec)
- may add H2 antihistamines (ranitidine) for severe or persistent urticaria
- glucocorticosteroids for refractory cases
- zyrtec should be dosed BID
- doxepin, TCAs with potent antihistamine properties, or Xolair may be useful in chronic urticaria
what is the etiology of seborrheic dermatitis?
- related to a pathologic overproduction of sebum
- may involve an inflammatory rxn to the yeast Malassezia
how does seborrheic dermatitis present?
erythema with greasy, yellowish scale
- on T-zone of face, scalp, behind ears, central chest, intertrigo
- dandruff
- can affect intertriginous areas
when is the onset of seborrheic dermatitis typically?
puberty
what factors worsen seborrheic dermatitis?
- changes in seasons
- trauma
- stress
- Parkinson’s disease
- AIDS
- certain meds
what are some d/dx of seborrheic dermatitis?
- atopic or contact dermatitis
- rosacea
- perioral dermatitis
- tinea
- impetigo
what is the tx for seborrheic dermatitis?
- shampoo at least every other day (shampoos that contain salicylic acid, tar, selenium, sulfur, or zinc are especially helpful) - leave on for 5 min before washing off
- clobetasol 0.05% solution or derma-smoothe/FS (mineral/peanut oil + flucinolone 0.1%) for severe flaking on the scalp
- ketoconazole 2% cream BID (for face, ears, chest)
- hydrocortisone 2.5% cream - short term use during flares
- tacrolimus ointment or pimecrolimus cream as steroid sparing agents
what is the etiology of psoriasis?
multifactorial disease that appears to be influenced by genetic and immune-mediated components
how does psoriasis present?
red papules and plaques with adherent silvery scale
what are some triggers for psoriasis?
- physical trauma
- stress
- infection (strep, HIV)
- pregnancy
- meds
what drugs can trigger psoriasis?
- NSAIDs
- abx
- steroids
- antimalarials
- lithium
- ACE-Is
- BBs
- CCBs
- interferon
- tetanus
- antihistamines
what is an important ROS questions to ask those with psoriasis?
ask about joint pain - 10% of patients have psoriatic arthritis (refer to derm or rheum)
how do you estimate body surface area (BSA) of a skin lesion?
avg palm = 1%
disease severity:
- mild = <5%
- moderate = 5-10% BSA (refer to derm)
- severe = >10% BSA (refer to derm)
with what conditions is psoriasis associated?
- CVD
- smoking
- ETOH
- metabolic syndrome
- lymphoma
- depression
- suicide
describethe characteristics and distribution of psoriasis vulgaris
chronic and stationary - lesions can persist for years
distribution
- elbows
- knees
- scalp
- lumbosacral
- umbilicus
nail pitting and other nail changes common
describe Koebner’s phenomenon
- occurs in 20% of psoriasis patients
- non-specific trauma can lead to formation of psoriasis in the area of irritation
describe inverse psoriasis
- involvement limited to skin fold regions
- usually associated with minimal scaling
- distribution: axilla, inframammary region, genitocrural region, neck
- often confused with intertrigo
what are some topical tx for psoriasis?
- topical steroids
- hydrocortisone 2.5% ointment (low strength) - good for short term use on face, penis, and intertriginous areas
- triamcinolone 0.1% ointment (medium strength)
- clobetasol 0.05% ointment (high strength) - synthetic vitamin D
- dovonex (calcipotriene) cream - helps reduce scale - topical calcineurin inhibitors -steroid sparing agents (good for face, penis, intertriginous areas)
- protopic ointment
- elidel cream
what is a common tx regimen for psoriasis?
- calcipotriene BID Mon-Fri
- clobetasol oint BID Sat-Sun for lesions on trunk and extremities
- hydrocortisone or calcineurin inhibitor for face, penis, and intertriginous areas
what is the etiology of tinea pedis?
dermatophyte infection of the soles of the feet and interdigital spaces, commonly caused by trichophyton rubrum
in what population does tinea pedis typically present?
- increases with age
- M>F
how and where does tinea pedis present?
pruritic, scaling in a moccasin distribution, often with painful fissures between toes
what is one way to dx tinea pedis?
KOK prep
what are some d/dx of tinea pedis?
- contact dermatitis
- dyshidrotic eczema
- psoriasis
what is the tx for tinea pedis?
- topical -azoles (ketoconazole)
- topical allylamines (terbinafine)
- Castellani’s paint, which is esp good for interdigital webspaces
- apply to bottoms, sides, and interdigital areas of the feet once or twice/day for at least 2 weeks, depending on which agent is used
what is the etiology of onychomycosis?
a fungal infection of the toenails or fingernails
how does onychomycosis present?
asymptomatic subungal hyperkeratosis and onycholysis, usually yellow-white in color
how can you confirm dx of onychomycosis?
clip nail to send for PAS or put in dermatophyte medium
what are some d/dx of onychomycosis?
- lichen planus
- psoriasis
- trauma
how do you tx onychomycosis?
- oral terbinafine, itraconazole
how long should you tx w/ oral antifungals for onychomycosis?
- 6 weeks for fingernails
- 12 weeks for toenails
what diagnostics should you check before tx w/ oral antifungals for onychomycosis? when should you recheck these?
- Cr
- LFTs
- CBC
- recheck if tx > 6 weeks
what tx can you try for onychomycosis when orals are contraindicated 2/2 liver disease?
- ciclopirox lacquer OR
- urea 40% w/ topical terbinafine
these are often not effective
- Jublia is new topical solution on the market, but tx is 48 weeks!
what is some education you should provide patients about how long it takes to tx onychomycosis, recurrence, and maintenance?
- inform pts that it can take a year for entire nail to grow out and appear normal
- recurrence is common even after systemic tx
- clean shoes and used topicals as maintenance
what is the etiology of intertrigo?
an inflammatory condition of skin folds resulting from heat, moisture, and friction
- often colonized by infection - usually candida but can also be bacterial, fungal, or viral
- a common complication of obesity and diabetes
how and where does intertrigo present?
erythema, cracking, and maceration with burning and itching at sites in which skin surfaces are in close proximity (axillae, perineum, inframammary creases, abdominal folds, inguinal creases)
what are some d/dx of intertrigo?
- contact dermatits
- seborrheic dermatitis
- cellulitis
- inverse psoriasis
- acanthuses nigrans
what is the tx for intertrigo?
- barrier creams such as zinc oxide paste
- compresses with Burow solution 1:40 or dilute vinegar
- absorbent powders and moisture-wicking undergarments
- exposing the skin folds to air
- topical antifungal agents for secondary infections (i.e. clotrimazole, econazole, ciclopirox, miconazole, ketoconazole, nystatin)
what is the etiology of scabies?
sarcoptes scabiei
- in developed countries, scabies occur primarily in institutional settings and LTC facilities; also common among children
how and where do scabies present?
- extremely itchy, especially at night
- often involves armpits, groin, umbilicus, wrists, fingerwebs, nipples
- primary lesions typically include small papules, vesicles, and burrows
what are some d/dx for scabies?
- atopic dermatitis
- bug bites
- psoriasis
what is the tx for scabies?
- topical antiscabietic agents (Permethrin 5%) are applied from the neck down w/ repeat application in 7 days
- oral ivermectin is also effective
how long will itching last and how can we help relieve it?
- pruritis may continue for up to 2 weeks after successful tx
- antipruritic agents (i.e. sedating antihistamines) and/or antimicrobial agents (for secondary infection) may be needed
what is important patient and family education regarding scabies?
all family members and close contacts must be evaluated and tx for scabies, even if they do not have symptoms
by what are itchy papules on the penis most commonly caused?
scabies
what is the etiology of zoster aka “shingles”?
reactivation of varicella-zoster virus (VZV) in a dermatome
what age does zoster aka “shingles” typically present?
a person of any age with a prior hx of varicella infection may develop zoster, but incidence increases with age 2/2 declining immunity
what are the 2 phases of zoster aka “shingles” presentation?
- pre-eruptive phase
- active eruptive phase
how does each phase of zoster aka “shingles” present?
- pre-eruptive phase: characterized by unusual skin sensations or pain w/in the affected dermatome that heralds the onset of lesions by 48-72 hours
- active eruptive phase: marked by lesions that begin as erythematous macules and quickly develop into vesicles; new lesions form over 3-5 days
- lesions in the eruptive phase tend to resolve over 10-15 days
- can be very painful and cause chronic neuralgia
what are some d/dx for zoster aka “shingles”?
- poison ivy
- atopic dermatitis
what is the tx for zoster aka “shingles”?
antivirals (i.e. acyclovir, valacyclovir, and famciclovir)
- patients are infections until the lesions have dried
- zostavax for people ages 50+ can help prevent zoster
what is an important form of zoster not to miss?
- herpes zoster ophthalmicus
- involves trigeminal (5th cranial) nerve
- vescicles may appear on the tip or inside nose (Hutchinson sign)
- urgent referral to ophthalmology is required
what is the etiology of folliculitis?
- primary inflammation of the hair follicle resulting from infections, follicular trauma, or occlusion
- superficial folliculitis is common and often self-limited
who does folliculitis most commonly affect?
affects all races, ages, and sexes equally
how does folliculitis present?
erythematous, folliculocentric papules and pustules associated with pruritis or mild discomfort
what are some d/dx of folliculitis?
- acne
- contact dermatitis
- milia
- miliaria
- insect bites
what is the tx for folliculitis?
- uncomplicated superficial folliculitis can be treated w/ abx soap and good hand washing technique
= refractory or deep lesions w/ a suspected infectious etiology may need empiric tx w/ topical and/or oral abx that cover gram-positive organisms (choose a drug that covers MRSA in areas of high prevalence or in predisposed patients) - mupirocin ointment in the nasal vestibule BID for 5 days may eliminate S. aureus carrier state in recurrent folliculitis
what is the prevalence of MSSA and MRSA colonization/infection?
- ~25-30% of population is colonized w/ MSSA (usually found on skin in nasal passages)
- half of patients presenting for eval of skin infection has MRSA+ cx
how does community acquired MRSA (CA-MRSA) present?
- infections usually manifest as folliculitis or a similar skin infection
- patients often present with a “spider bite” or “infected pimple”
how is community acquired MRSA (CA-MRSA) transmitted?
through an open wound or from contact w/ a community acquired MRSA (CA-MRSA) carrier
what is tx for community acquired MRSA (CA-MRSA)?
I&D of the abscess and tx w/ appropriate abx when indicated
- wound exudates should be cultures to determine the causative organism and appropriate abx
what oral abx are best for community acquired MRSA (CA-MRSA), when indicated?
- trimethoprim-sulfamethoxazole DS BID W/ OR W/O - rifampin 600 mg/day - doxycycline 100 mg BID - clindamycin 450 mg TID
what is rosacea?
CHRONIC inflammatory disease of the central face
what are the 4 types of rosacea?
- erythematotelangiectatic
- papulopustular
- phymatous (glandular rosacea)
- ocular
what is the etiology of rosacea?
unknown, but the following may play a role:
- vasculature
- climatic exposures
- chemicals and ingested agents
- pilosebaceous unit abnormalities
- microbial organisms
- increased neoangiogenesis
in what populations is rosacea more common?
fair-skinned people of European and Celtic origin
what are some d/dx of rosacea?
- lupus
- seborrheic dermatitis
- perioral dermatitis
what are some characteristics of erythematotelangiectatic rosacea?
- hx flushing
- central facial erythema
- telangiectasis not essential
what are some characteristics of papulopustular rosacea?
- central facial erythema
- papules or pustules
- edema
what are some characteristics of phymatous rosacea?
- thickened, edematous skin
- nose most commonly affected
- sebaceous hyperplasia
what are some characteristics of ocular rosacea?
- ocular sx occur prior to cutaneous manifestations in ~20% of patients
- blepharitis and conjunctivitis
- staph infectious common
what are some topical tx for rosacea?
- sunscreen!!! daily broad spectrum sunscreen is recommended for all pts w/ rosacea
- metronidazole
- azelaic acid
- sodium sulfacetamide/sulfur
- protopic
- erythromycin
- clindamycin
- tretinoin
- benzoyl peroxide
what are some systemic tx for rosacea?
- tetracyclines (DCN and MCN > TCN)
- azithromycin
- metronidazole
- isotretinoin
what is a typical tx regimen for rosacea?
tretinoin at night bc reacts to sunlight and benzoyl peroxide in AM - spread out so they don’t cancel each other out
what are some ROS questions to ask someone presenting with alopecia?
- detailed hx
- onset
- stress
- meds
- diet
- grooming
- family hx
2 types of alopecia pattern
- patchy
- diffuse
2 types of alopecia sequelae
- scarring (loss of hair follicle openings - requires biopsy)
- non-scarring
what are some characteristics of telogen effluvium? (contributing factors, scarring vs. not, pattern, etc.)
- caused by stress
- hair pull test
- > 25% telogen hair
- non-scarring
diffuse - consider: thyroid dysfunction, drugs, nutrition
- check labs: CBC, TSH, iron, ferritin
what are some characteristics of androgenic alopecia? (contributing factors, scarring vs. not, pattern, etc.)
- family hx
- non-scarring
- male pattern
- consider androgen excess in females
what are some characteristics of trichotillomania? (contributing factors, scarring vs. not, pattern, etc.)
- cause is emotional
- broken hairs
- non-scarring
- patchy
- d/dx: areata, fungal
what are some characteristics of alopecia areata? (contributing factors, scarring vs. not, pattern, etc.)
- acute onset
- smooth patches
- autoimmune (consider DM, thyroid, vitiligo)
- exclamation point hairs
- non-scarring
- d/dx: tricho, fungal
- tx: topical steroids, ILK, PUVA
what are some characteristics of lupus erythematosus? (contributing factors, scarring vs. not, pattern, etc.)
- scarring or non-scarring
- tx: steroids, hydroxychloroquine
what are some characteristics of tinea capitis? (contributing factors, scarring vs. not, pattern, etc.)
- seborrea-like
- patchy
- broken hair
- occipital lymph nodes
- tx: requires systemic: griseofulvin, terbinafine, or itraconazole for 1-3 months
- follow LFTs on meds
what are some examples of scarring types of alopecia?
- lichen planopilaris: F>M, pustular, erythema, localized
- folliculitis decalvans: expanding patch w/ pustules to periphery
- acne keloidalis nuchae: nape of neck
what is bullous pemphigoid?
autoimmune blistering disease
how is bullous pemphigoid detected/diagnosed?
presence of circulating IgG autoantibodies (BP230, BP180)
what are the 2 phases of bullous pemphigoid and how does each present?
- prodromal period: pruritic eczematous/urticarial lesions for weeks - months
- bullous phase: abrupt onset widespread blister formation- tense, oval, and round
what parts of the body does bullous pemphigoid most commonly present?
- abdomen
- flexor sufaces
what are some PE components to include when assessing someone who possibly has bullous pemphigoid?
- ocular involvement
- mucosal involvement
- genitalia involvement
- negative Nilolsky
what are some common triggers of bullous pemphigoid?
- pharmacologic
- lasix
- phenacetin
- enalapril
- NSAIDs
- vaccines
- ampicillin
- penicillin
- cephalexin - traumatic
- burns
- radiation - infections
- human herpes virus
- Epstein barr
- CMV
- Hep B and C
what are some d/dx of bullous pemphigoid?
- contact dermatitis
- urticaria
- bites
what are the goals of tx of bullous pemphigoid?
- promote healing
- reduce itching
- preventing secondary infections
what is the tx for bullous pemphigoid?
- topical steroids
- systemic oral steroids
- referral for biologic tx: methotrexate, rituximab, cellcept, azathioprine
