Derm Flashcards
What are the 3 most common skin and soft tissue infections? what is included in their differential dx?
Cellulitis Erysipelas Skin abscesses Gout DVT Venous stasis dermatitis (Bilateral)
Skin layers affected in Cellulitis, Erysipelas and Skin abscesses?
cell - deeper dermis and subcutaneous fat
erys - upper dermis and superficial lymphatics
skin ab - upper and deeper dermis
Name skin condition: unilateral presentation raised above level of surrounding skin with clear demarcations b/w involved and uninvolved skin. Non-purulent. acute onset of sx.
Erysipelas
b-hemolytic strep can present with butterfly rash on face**
pathogen responsible for: erysipelas cellulitis abscesses
ery - B-hemolytic strep
cell - b-hemolytic strep, staph aureus, MRSA
abscesses: sstaph aureus, MRSA
risk factors for Cellulitis, Erysipelas and Skin abscesses?
Skin barrier disruption
Preexisting skin conditions (eczema, impetigo, tinea)
Skin inflammation
Edema due to lymphatic drainage or venous insufficiency (venous stasis presents BILATERALLY)
Obesity
Immunosiuppression
Close contact w/ people w/ MRSA
complications of Cellulitis, Erysipelas and Skin abscesses?
NF
bacteremia and sepsis - blood cx
osteomyelitis - x-rays
septic joint - aspiration
Pasteurella multocida
cat bite
Capnocytophaga canimorsus
dog bite
Erysipelothrix rhusiopathiae
farm animals
Vibrio vulnificus
water borne = step on something at beach
Pseudomonas aeruginosa
must cover if pt is a diabetic
Sporothrix schenckii
rose gardener
Define impetigo
contagious superficial bacterial infection seen most commonly on the face seen in children age 2-5 more common in summer and fall
Primary vs secondary impetigo
primary - direct bacterial invasion of normal skin
secondary - infection at sites of skin trauma
what is the most common bacterial infection in children?
impetigo 3rd most common skin condition in children
Name the skin condition
non-bullous impetigo
Most common form
S auerus
Name skin condition?
bullous impetigo
vesicles enlarge to form flaccid bullae with clear fluid
becomes darker -> rupters leaving thin brown crust
fewer lesions - seen primarily in children
trunk more affected
S.aureus strain that produces a toxin that causes cleavage of superficial skin layer
Nsme skin condition?
Impetigo + Ecthyma
ulcrative form
lesions extend through epidermis to deep dermis
“punched out” ulcers covered in yellow crusts
Group A beta hemolytic strep pyrogenes
Treatment for Impetigo + ecthyma
ORAL
Dicloxacillin 250 mg QID
cephalexin 250 mg QID
erythromycin (penicillin allergy)
clindamycin (MRSA suspected)
Treatment for non-bullous and bullous impetigo?
TOPICALS
mupirocin (bactroban) TID
retapamulin (Altabax) BID
ORAL - if extensive
dicloxacillin
cephalexin
erythromycin (for penicillin allergy)
clindamycin (if mRSA suspected)
Complications of impetigo?
poststreptococcal glomerulonephritis
edema
HT
fever
hematuria
all seen 1-2 wks post infection
MRSA CA vs MRSA HA
CA -
- Sensitive to non-beta-lactam antibiotics
- Initially reported in IVDU
- Most frequent cause of SSTI presenting to US ERs and ambulatory clinics
HA
- Infection that occurs >48 hours following hospitalization
- Leading cause of surgical site infection
- Multidrug resistance
Treatment for MRSA
PO
trimethoprim-sulfamethoxazole
clindamycin
doxycycline
minocycline
IV
vancomycin
daptomycin
Define clinical presentation of Urticaria
intensley puritic raised erythematous plaques with central pallor
ANY area of body can be affected
waxing and waning (lesions appear and disapper w/in 24 hrs) - more severe at night
sometimes accompanied by angioedema (lips, extremeties, genitals)
Etiology and Pathophysiology of urticaria
infections
IgE mediated
direct mast cell activation (narcotics, muscle relaxants, radiocontrast agents, vanocmycin)
physical stimuli
mediated by mast cells in superficial dermis and basophils
release multiple mediators including histamine and vasodilatory mediators
Name medications that result in direct mast cell activation?
narcotics/opiods
muscle relaxants
radiocontrast agents
vancomycin
Management of urticaria
focus on short term relief of puritis and angioedema (2/3 will spontaneously resolve)
H1 antihistamines
- Diphenhydramine (Benadryl)
- Chlopheniramine (chlor-trimenton)
- Hydroxyzine (Vistaril)
- Certirizine (Zyrtec)
- Loratadine (Claritin)
- Fexofenadine (allegra)
H2 antihistamines
- Ranitidine (zantac)
- Nizatidine (Axid)
- Famotidine (Pepcid)
- Cimetidine (Tagamet)
glucocorticoids for sx lasting longer then 2-3 days (SEVERE)
prednisone 30-60 mg taper over 5-7 days
Name H1 antihistamines used to tx urticaria
- Diphenhydramine (Benadryl)
- Chlopheniramine (chlor-trimenton)
- Hydroxyzine (Vistaril)
- Certirizine (Zyrtec)
- Loratadine (Claritin)
- Fexofenadine (allegra)
Name H2 antihistamines used to tx urticaria
- Ranitidine (zantac)
- Nizatidine (Axid)
- Famotidine (Pepcid)
- Cimetidine (Tagamet)
Define Lipoma
most common benign soft tissue neoplasm (!% of population)
soft, painless, round or oval subcutaneous nodule
mature fat cells enclosed by a thin fibrous capsule - rarely inolve fascia or deeper muscles (superficial)
common on upper extremities and trunk
Lipoma and genetics
cause of lipomas are unknown - some have genetic predisposition
familial multiple lipomatosis - multiple lipomas in multiple family members
Gardner Syndrome - rare inherited condition characterized by familial adenomatous polyposis (multiple lipomas), common on face, scalp, neck and trunk
Tx for lipomas
none
if bothersome - surgical excision of fat cells and fibrous capsule (cosmetic or pain reasons)
What is the most common cutaneous cyst?
Epidermal inclusion cysts
firm, skin colored dermal nodules with visable central punctum
asymptomatic, can be red and inflammed
freely moveable
Pathophysiology of epidermal inclusion cysts
implantation and proliferation of epithelial elements into dermis (dead skin implants into hair follicle) from trauma or comedome
cyst wall consists of normal stratified squamous epithelium
Tx for epidermal inclusion cysts
asymptomatic - no tx, will resolve on own
Not inflammed - punch excision of cyst and drainage = must pull out all of “cheesy inside” along with capsule or cyst will reform
intralesional injections w/ triamcinolone - inject cyst w/ steroid to decrease size and inflammation
•Most common cutaneous disorder affecting adolescents and young adults (mostly males) that resolves in third decade of life
acne
Four main factors are involved in acne patho
- Follicular hyperkeratinization
- Increased sebum production - provides growth medium for c. acnes
- Cutibacterium ances (FKA Propionibacterium acnes) within the follicle - Microcomedones provides an anaerobic lipid-rich environment for bacteria
- Inflammation -Microcomedones provides an anaerobic lipid-rich environment for bacteria
cause of infantile acne?
androgens
Contributes to the development of acne through stimulating the growth and secretory function of the sebaceous gland
Labs ordered in pt w/ acne.
DHEA-S
total testosterone
free testosterone
4 types of Rosacea?
- Erythematotelangiectatic
- Papulopustular
- Phymatous
- Ocular rosacea
cause of Rosecea
Cause is unknown, possible factors include
- Immune dysfunction
- Inflammatory reactions to cutaneous microorganisms
- UV damage
- Vascular dysfunction
Dx? and Tx?
Erythematotelangiectatic or “classic rosecea”
FIRST LINE – avoid triggers, sun protection and decrease alc intake
SECOND LINE – laser and light-based therapy
Pharmacotherapy – alpha adrenergic agonists
- Topical brimonidine (Mirvaso)
- Topical oxymetazoline (Rhofade)
type of roseca more common in MEN
Phymatous
Pt presents w/ papules and pustules in central face. On examination you see reddness extending beyond the follicle.
Dx and Tx:
Papulopustular R
Topical metronidazole 0.75% (most common)
Azelaic acid 20% cream
Ivermectin 1% cream
Oral
- Tetracycline, doxy, minocycline
- Isotretinoin 0.3 mg/kg QD
Tx of phymatous Rosecea
Oral isotretinoin 0.3-1 mg/kg QD in early disease
Laser ablation and surgery in advanced disease
Side effect seen in more then 50% of pts w/ Rosecea
Ocular!!!!!
Lesions are characterized by well-demarcated erythematous plaques with silver scale. Dx??
Psoriasis
•When compared to normal epidermis, psoriasis epidermis shows:
- Increased number of epidermal stem cells
- Increased number of cells undergoing DNA synthesis
- A shortened cell cycle time of keratinocytes
- A decreased turnover time of epidermis
Most common type of psoriasis and where do the lesions present?
chronic plaque
symmetrically distributed on:
Scalp, extensor elbows, Knees and gluteal cleft most common sites
pt is a 10 y/o boy presnting to clinic w/ a rash on trunk and proximal extremties. you recognize the child as he came into clinic a few weeks ago to be tx for strep pharyngitis.
Dx and Tx????
guttate psoriasis
will resolve and not likely lead to chronic psoriasis
Pt presents w/ rash. you see no visable scaling. she was previously prescribed ketoconazole by another provider. after no relief of sx she presents to you.
dx??
Inverse psoriasis
most common clinical manifestation in pts w/ psoriatic arthritis?
nail psoriasis (nail pitting)
pts presents w/ fever, diarrhea, leukocytosis and hypocalcemia. on examination you see widespread erythema, scaling, and sheets of superficial pustules.
Dx and what could have caused this?
pustular psoriasis
pregnancy, infection or withdrawal of oral glucocorticoids
what is erythrodermic psoriasis
Generalized erythema and scaling from head to toe
inpatient management
what is auspitz sign
pinpoint bleeding after removal of plaque
dx of psoriasis
Tx choices for MILD psoriasis
less then 5% BSA
emollients
top corticosteroids - Hydrcortisone 1%, Triamcinolone 0.1%, Flucinonide 0.05%
Tar-T gel (neutrogena)
Vitamin D analogs
topical retinods (tazarotene)
Tx for mod-severe psoriasis ?
5-10% BSA
phototherapy (photochemotherapy)
- w/ either oral or bath psoralen followed by UVA radiation
- Increased cancer risk of non-melanoma skin cancer and melanoma
excrimer laser
methotrexate
cyclosporine
aprimelast
- •TNF- alpha inhibitors*
- •IL-17 inhibitors*
- •IL-23 and related cytokine inhibitor*
- •*specialist managed*
define hidradenitis suppurativa and the pathophys of the dz
Apocrine sweat gland dysfunction
- Follicular occlusion, follicular rupture and associated immune response
- Ductal keratinocyte proliferation -> ductal plugging -> expansion -> rupture and release of contents -> stimulating immune response and leading to sinus tracts in skin
Describe the 3 stages of the Hurley staging system for HS.
1: abscess formation
2: recurrent abscess formation w/ sinus tract formation and scarring
3: Diffuse involvement of multiple connected sinus tracts
Dx (stage) and tx
Avoidance of skin trauma
Smoking cessation
Weight management
Antiseptics – chlorhexidine 4% once/week
Emollients
Management of comorbidities
Dx (stage) and tx
Oral tetracyclines for several months
Clindamycin 300 mg BID and rifampin 600 mg QD
Oral retinoids
Antiadrenergic therapies – OCPS, spironolactone
Punch biopsy of fresh lesion (drain tracts
dx (stage) and Tx
TNF- alpha inhibitors
Adalimumab
Infliximumab
Systemic glucocorticoids – prednisone
Cyclosporin
Surgery
along w/ hair loss what is another common sx in pts w/ alopecia?
Onychorrhexis – longitudinal fissuring of nail plate
pathophys of alopecia
- Autoimmune disease in which hair follicles in the growth phase (anagen) prematurely transitions to the non-proliferative involution (catagen) and resting (telogen) phase
- This leads to sudden hair shedding and inhibition of hair regrowth
- T-cell mediated
- Inappropriate trigger of immune response against follicular antigens
Commonly presents
diagnostic finding of pts w/ alopecia
there are 2****
exclamation point at hair margins
•Skin biopsy -> Peribulbar lymphatic infiltrates surrounding follicles (swarm of bees)
first line tx for limited patchy hairloss
- Topical or intralesional corticosteroids
- Triamcinolone 2.5-5 mg/ml
- Betamethasone dipropionate 0.05%
or topical
Monoxidil
anthralin cream
PUVA
first line tx for extensive hair loss
- Topical immunotherapy
- Diphenylcyclopropenone (DPCP)
- Squaric acid dinutyl ester (SADBE)
Systemic therapies
Oral glucocorticoids
Sulfasalazine
Methotrexate
Cyclosporin
Biologics
what is eczema (dermatitis) closely related to?
asthma
allergic rhinitis
what type of hypersenitivity rxn is atopic derm
type I IgE mediated
•Intense itching produced by mast cells and basophils in dermis.
where does atopic dermatitis usually present
•Presents on flexor surfaces, neck eyelids, face, dorsum of hands and feet
** face and extensor/flexor in children
you dx your pt w/ atopic dermatitis but she DOES not want steroid creams and wants something she can use longer term?
What do you prescribe?
- Pimecrolimus (Elidel)
- Nonsteroidal
- Addition/alternative to topical steroids.
- Good for long term use.
OR
- Topical immunemodulators
- Tacrolimus (Protopic) -> Nonsteroidal (cytokine inhibitor)
- Used as an addition/alternative to topical steroids.
pt presents w/ coin shaped pruritic patches and plaques in clusters on her legs.
Name another condition this resembles and what you would do to rule it out.
Dx and TX
tinea corporis - usually clear in center
r/o w/ KOH swab
dx Nummular Eczema
tx
- Acute: Intermediate strength topcial steroid (triamcinalone cream 0.1%).
- Or if severe, high potency (Clobetasol ointment) +/- occlusion.
Long term: treatment with less potent topical steroids
pt presents w/ small vesicles appear on hands and feet complaning of pruritus
dx? and cause?
Dyshydrosis
•inflammation and foci of intercellular edema (spongiosis) which becomes loculated in the skin of the palm and soles.
tx dyshydrosis
- Mild cleansers (Cetaphil)
- Emollient barrier creams, protective gloves, avoidance of irritants.
- Burow’s solution. (Antibacterial Astringent)
- Topical corticosteroids are the mainstay.
- High: Clobetasol Ointment for acute flare
- Med: (triamcinolone 0.1% or Fluocinonide 0.05%) with or without occlusive dressing.
- Protopic and Elidel for long term management
Dx and Tx
stasis dermatitis - seen mostly in women
- Elastic compression stockings
- Burrow’s solution
- Moderate topical steroid: Desonide, Triamcinalone cream.
- Treat any secondary infection with po Abx. (Keflex)
woman presents in clinic w/ a rash showing clustered papulopustules on erythematous bases w/ scale around her mouth. she tells you she just finished using hydrocortisone cream.
dx and tx
- Topical antibiotics: Metronidazole or erythromycin.
- Severe cases may require oral minocylcin / doxycycline.
- *Avoid topical steroids* - will exacerbate sx
how do we tx Seborrheic Dermatitis on both scalp and face??
- Scalp: zinc shampoo, Ketoconazole shampoo
- Face, intertiriginous areas: Low potency topical steroids
(Desonide or Valisone Cream)
offending agent: p. ovale
pt presents w/ hardened area over wrist. It is a solitary pruritic eczematous eruption that appears Lichenified.
dx and tx
Lichen Simplex Chronicus
Intermediate strength topical steroid.
- Triamcinalone cream 0.1% prn
- Occlusion when able
- Oral antihistamines
- Protopic
- Elidel 1%
upon a yearly skin check of your 35 y/o pt. she complaing of a Purple, Polygonal, Pruritic, Papule on her scalp. w/ further examination of the mouth you see white lesions in the buccal mucosa.
Dx? Tx
Lichen Planus
Potent topical steroids with occlusion dressing, or intralesional steroid injections.
a 70 y/o pt comes in for a skin check. you see this. it appears to be stuck on and hace a warty appearance.
Dx tX?
Seborrheic Keratosis
none
•Vascular neoplasm brought on by genetic factors, hormonal factors, immunodeficiency or infection with Human Herpes Virus 8????
Kaposi sarcoma
Pt presents to clinic w/ this lesion on her face. on palpation you feel a sandpaper texture.
Dx and TX
actinic keratosis
Precursor for squamous cell carc.
tx of actinic keratosis w/ limited number of lesions
For extensive broad and numerous lesions???
•Cryotherapy
Imiquimod (less irritating then 5-Fu)
what is the most common cancer
basal cell
pathophys of basal cell
- BCC arise from immature pluripotential cells associated with the hair follicle. Mutations activate pathway that controls cell growth.
- Mutation also activates oncogenes and inactivates tumor suppressor genes, leading to tumor growth.
what is characteristic ft of all basal cell carc.
Bleeding w/out pain
Pt presents to clinic w/ waxy, pearly, semitranslucent nodules or papules with “rolled edge” forming around a central depression that is ulcerated, crusted and bleeding.
Dx ??
nodular basal cell
what form of skin cancer is most common in hispanics and asians??
Pigmented
on examination appears appears as a dry scaly lesion, superficial flat growths,
Dx?
Superficial BCC
pt arrives w/ complaints of a new plaque on side of nose. on physical exam you notice a white sclerotic plaque with telangiectasia.
Dx?
Morpheaform (sclerosing) BCC