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Dermatology ICM

Terms in this set (134)

keratinocyte function
- barrier function: stratum corner
- produce cytokines and inflammatory molecules
- make antimicrobial proteins and lipid
- drug metabolism
vitiligo
loss of melanocytes through autoimmune destruction
macule
circumscribed, flat (NON-PALPABLE) discoloration
-may be brown, blue red or hypo pigmented
--> Patch if >than several cm
elevated solid lesion up to 0.5-1cm in diameter that varies in color
papule --> becomes plaque if become confluent
circumscribed, elevated solid lesion >1cm in diameter often formed by confluence of papules
plaque
circumscribed, elevated, solid lesion more than 0.5 to 1cm in diameter
nodule
- large nodule = tumor
firm, edematous plaque resulting from infiltration of dermis with fluid
Wheal
circumscribed collection of leukocytes and free fluid that varies in size
pustule
circumscribed collection of free fluid up to 0.5 cm in diameter
vesicle
circumscribed collection of fluid greater than 0.5 cm
bulla
excess dead epidermal cells that are produced by abnormal keratinization and shedding
scales
collection of dried serum and cellular debris
Crust (Scab)
focal loss of epidermis (don't penetrate below DEJ so don't scar)
erosion
often linear erosion caused by scratching
excoriation
Ulcer def
focal loss of epidermis and dermis
- heal with scarring
fissure
- linear loss of epidermis and dermis with sharply defined, nearly vertical walls
depression of skin resulting from thinning of epidermis or dermis
atrophy
abnormal formation of CT implying dermal damage
Scar
Comedone
plug of sebaceous and keratinaceous debris lodged in opening of hair follicle
-follicular orifice may be widened or narrowed
Lichenification
area of thickened epidermis induced by scratching
burrow
narrow, elevated, tortuous channel in skin created by a parasite
small cysts under skin- have walls containing epidermis and often associated with scarring
milia
cyst
circumscribed lesion with a wall and lumen
telangiectasia
dilated superficial blood vessels
Petechiae
circumscribed deposit of blood less than 0.5 cm in diameter
purpura
circumscribed deposit of blood greater than 0.5 cm in diameter
infantile hemangioma
benign tumor of vascular endothelium
-grow in 1st year then regress by 5-10yrs
-clinically heterogenous
port-wine stain
superficial vascular malformation
- dont regress
-potential for thickening and development of benign vascular papules
- treatment: vascular lasers
sturge-Weber Syndrome:
-Facial Port-wine Stain + underlying CNS involvement
- Seizures, mental deficiency, intracranial/intraocular bleeding
-only in association with V1 PWS
-Bilateral lesions are at high risk
congenital melanocytic nevi
- benign hamartomas of melanocytic cells
- 3 types: small, medium, large
- management: monitoring, surgical removal
infection with itchy lesions at different stages. appears as dew drop on a rose petal
Varicella
infection with cough, coryza, conjunctivitis, photophobia and fever
- rash begins on 4-5th day (morbilliform eruption)
Rubeola (measles)
kopeck spots
small, irregular bright-red spots with central bluish-white speck on buccal mucosa
-see in measles enanthem
german measles (rubella)
milder form of rubeola
- encephalitis, thrombocytopenia
- Rash on face and spread to trunk and extremities
erythema infectiosum
- Parvovirus B19
- slapped cheeks, fishnet erythema, recurrence
roseola infantum
- HHV6,7
- high fever, well child
- pale-pink macular rash begins as fever fades
Hand-Foot-Mouth Dx
- Coxsackie Virus A16
- sore lesions on mouth, less sx on hands-feet
Scarlet fever
-Strep toxin
-fever, pharyngitis, strawberry tongue
-Rash = begins on neck and spreads to trunk, extremities
Etiology and pathogenesis of Urticaria
-most commonly viral, food and drug etiologies; also SPACE (sun, pressure, aquagenic, cold, exercise)
- Pathogenesis: dilated (erythema), leaky (edema) vessels
- largely due to histamine effect on small dermal vessels
**Erythema, edema, evanescent
erythema multiforme minor and major causes
-Minor: Herpes simplex virus (esp if recurrent)
- Major (Steven- Johnson Syndrome): most due to drugs
* immune complexes and cytotoxic T cells with apoptosis
Presentation of erythema multiforme
target lesions with dusky center
Target vs targeted lesions
-Target:concentric circles (3 total), central duskiness, wide pale circle in between. outer thin moderately dark erythematous circle
-Targetoid: Zonality as with above but without 3 distinct concentric circles
etiology and pathogenesis of dermatomyositis
-most idiopathic
- Definite role of UV radiation in disease induction, MAC has role
Diagnostic criteria for Dermatomyositis
- skin features: Heliotrope rash, malaria rash, shawl sign, Gorton's Papules, periungual telangiectasis
-proximal muscle weakness
- muscle enzyme abnormalities
-characteristic EMG abnormalities
-Muscle biopsy
what disease may you see puffy skin with yellowish tint, loss of lateral eyebrows and dry,course brittle hair
Hypothyroidism (myxedema)
necrobiosis lipoidica
- well demarcated areas of epidermal atrophy
- see in diabetics
eruptive xanthomas
-Firm, flesh-colored to yellowish papule and plaques
-often seen in metabolic disorders
porphyria cutanea tarda
- blisters (bull)
- scarring
- dorsal surfaces of hands
- hypertrichosifs: abnormal amount of hair growth
lymphoma cutis
-Cutaneous T cell lymphoma, mycosis fungicides type
-nodules
- Macules and patches
leukemia cutis
purpuric papule and plaques
4 components of Acne
-keratinous impaction of pilosebaceous canal -> comedones plugs
- increased sebaceous activity
- accumulation of sebaceous and keratinous debri behind obstruction
-proliferation of anaerobic bacteria (P. Acne)
Comedone plug treatments
- topical
Retinoic Acid (Retina-A)
Benzoyl Peroxide
Propionibacterium Acne treatments
-Antibiotics
Topical: Erythromycin, clindamycin
Systemic: Tetracycline, erythromycin
Treatment for increased sebaceous activity
Systemic retinoids and or anti androgens (Contraceptive pills, aldactone)
erythematous patches covered by yellowish crust. lesions are most frequently around the mouth
Non-Bullous impetigo
-B hemolytic strep is most frequently found in this type of impetigo
Bull with cloudy contents, often surrounded by an erythematous halo. rupture easily and rapidly replaced by extensive crusty patches
Bulls impetigo
-classically caused by S. Aureus
fungi with spaghetti and meat balls appearance
malassexia furfur
Irritant vs contact dermatitis
Irritant: toxic injury to skin by chemical; direct but nonspecific effect
Allergic: Immunologic, T-cell mediated rxn (Type IV)
allergic contact dermatitis pathogenesis
- delayed hypersensitivity rxn
Antigen > skin protein > Langerhan cells > sensitized T cells develop
what you see on histology in allergic contact dermatitis
-intracellular edema (spongiosis)
- intraepidermal vesicles
- Lymphocytic and eosinophilic dermal infiltrate
common causes allergic contact dermatitis
poison ivy/oak/sumac, nickel, perfumes, rubber compounds
herpes infection on histology
- infected cells > large "Balloon" cells > multinucleate giant cells
- intraepidermal vesicles
when to use Tzank prep
Herpes
intraepidermal and sub epidermal autoimmune bullous diseases
-intra: pemphigus vulgaris
- Sub: Bullous pemphigoid, dermatitis herpetiformis
what does pemphigus look like under immunofluorescence
- Ig deposition between keratinocytes
-circulating Ig directed at intercellular spaces of epidermis
Pathogenesis of Pemphigus
-Autoimmune disease in which circulating Ab bind to skin and induce release of mediators of inflammation -> acantholysis -> blister formation
Bullous pemphigoid on Immunofluorescence
- Ig and complement deposition along basement membrane zone
- circulating auto-Ab directed against the Basement membrane zone
Dermatitis herpetiformis on Immunofluorescence
- Ig (IgA) deposition along basement membrane zone is granular
Dermatitis herpetiformis pathogenesis
- Antigen-Ab complexes are deposited in skin where they induce inflammatory response -> sub epidermal vesicles and pruritis
how to distinguish acne and rosacia
acne have comedones
Eumelanin
brown-black
Phaeomelanin
Yellow-red
tinea capitis
fungal infection on head
often causes hair loss
hypo pigmented fungal infection
tinea versicolor: malassezia furfur
-impedes synthesis of melanin
cause of molluscum contagiosum
poxvirus
insect with 3 bits together
bedbug
insect causing targeted lseions
ixodus tick
Lyme dx
inflammatory eruption with increased epidermal proliferation resulting in a thickened statum corner**
- onset at any age
- characterized by papule and plaques with scales
Psoriasis
skin conditions with parakeratosis, acanthuses (thick epidermis) and inflammatory cells
psoriasis
life threatening types of psoriasis
exfoliative or erythrodermic psoriasis
Koebner phenomena
psoriasis lesions occur at site of trauma
nail sign of sporiasis
Pits or oncholysis
superantigens precipitating psoriasis lesions
strep
well- defined, erythematous papule and plaques with silvery scale, dry
psoriasis
acute self limiting herald patch (oval scaly) thats primarily truncal and follows skin line
pityriasis rosea
-prolly HHV
Pityriasis rosea lesion characteristics
yellow thin plaques with trailing scale
-oriented along cleavage lines
secondary syphilis
-systemic dx: Fever, mucus membranes, headache, enlarged lymph nodes
-orange brown scale (copper penny) see on palms and soles a lot
flat-topped, violaceous papule and plaques, scale, violet colored and VERY itchy
lichen planes
-similar to drug reactions and GVHD
atopic dermatitis
Hx: asthma/hay fever/ hives
-family hx
-pruritis (erythema, lichenification, excoriations)
-IgE elevation
seborrheic dermatitis
symmetry, erythema papule, greasy, scale
-uknown cause: increase in AIDS, Parkinsons
-Pityrosporum
- nasolabial folds
-increased sebaceous gland oil
stasis dermatitis
-sharp border, erythema, brown, scale, crust, ulcers
- hard to treat when get ulcers
-related to venous disease
-edema, hemosiderin, fibrosis
Fish skin, scale, no erythema, white, brown
Ichthyosis
risk factors for basal cell CA
- fair skin, UV, family hx, radiation therapy, arsenic
pink dome-shaped papule which have pearly, rolled borders and telangiectasis, normally found on sun-exposed areas like face and arms
Basal cell carcinoma
Diagnosis of BCC
- skin biopsy only definitive diagnosis
BCC treatment
-Surgery: most often used and best cure rate
1. regular surgical excision (excise tumor with margin)
2. Mohs Microrgraphic surgery: tumor cut with almost no margin and then frozen and lok under microscope to see if residual tumor. remove if more margins and repeat until margins clear (better cure rates and cosmetic results)
3. Electrodessication and Curettage: visible tumor repeatedly scraped out and electrodessicated until no tumor remains
4. Cryosurgery: destruction of tumor with liquid nitrogen (not common)
- Imiquimod (cream) if superficial nodular BCC
- Radiation: use if extensive
prevention of BCC
sun protection
self-exam
regular exam by dermatologists
course/prognosis of BCC
-rarely mets
-untreated become very large and disfiguring
Actinic Keratosis risk factors
- fair skin
- significant UV exposure
-family Hx
-immunocompromised
Actinic keratosis appearance
-dry, red, scaly, hyperkeratotic papule and macule which are most commonly found on face, scalp and arms
-precancerous (can become squamous cell CA)
Actinic keratosis diagnosis
biopsy definitive
actinic keratosis treatment
-cryotherapy: liquid nitrogen applied to lesion
-Topics 5-FI
-Imiquimod cream
- Retinoids (when used regularly can help prevent formation of actinic keratoses)
Sq. Cell carcinoma Risk
- fair skin, UV exposure, family hx, arsenic, hydrocarbons, heat, radiation, scars, uncircumcised males, alcohol/tobacco, HPV
diagnosis, tx and appearance of SCC
-much variation: small, red, hard, scaly papule and plaques
-Skin biopsy definitive
-Tx same as BCC
prognosis of SCC
- uncommon mets but more common than SCC
Bowen Disease
SCC thats confined to epidermis without invasion into dermis
-appearance: red, slightly scaly patch/plaque
-better prognosis than SCC
Risk factors of melanoma
- intermittent sun exposure
-fair skinned
-genetic factors (Defective p16 Tumor suppressor)-
family history
-congenital nevi, dysplastic nevi
-immunosuppression
melanoma appearance
Asymmetry, Border irregularity, Color Variegation, Diameter >5cm, Enlargement
- Itch, burn, tender, bleed or ulcerate
Diagnosis of Melanoma
- skin biopsy
Tx of melanoma
-surgically excised
-if metastatic: also chemo and immunotheraputic regiments
-Survival low if distant metastasis (only 12% survival at 5 years)
Melanoma prognosis
- poor
- greater potential for metastasis
most common cutaneous neoplasm
seborrheic keratoses
distribution of Seborrheic keratosis
any cutaneous surface except mucus membranes
Appearance of seborrheic keratosis
macular or papular
- waxy yellow to dark brown color, velvety or verrucous, "Stuck on" appearance, grass appearance
- usually asymptomatic
dermatosis papulosa nigra
- seborrheic keratosis variant seen in darker skin tones
-distribution on face
Seborrheic keratosis treatment
- none unless symptomatic
-cryotherapy, electrosurgery, chemical peels or lazer
benign proliferations of melanocytes in skin that are extremely common
melanocytic nevi
nevi appearance
symmetric, regular borders, homogenous surface & color, round or oval shape
Types: Junctional, compounds or intradermal
nevi life cycle
- appear after 6-12 mo of age
-enlarge and increase in # early in childhood/Puberty, continue to increase in # through childhood/puberty, regress later
-may undergo eruptive growth in: adolescence, pregnancy, after steroids
Junctional nevi
nevus cells at junction between epidermis and dermis
-appear: small, round, flat/raised, light to dark brown/black
Compound Nevi
nevus cells at both the junction b/w the epidermis and dermis and within the dermis
-Raised, often papillomatous
dermal nevi
nevus cells in dermis
- raised, brown to flesh colored, smooth or papillary surface, rubbery texture
Actinic keratosis vs actinic cheilitis
*keratosis on skin (flesh to red color)
*cheilitis on lips (diffuse slight scaling)
-both pre-malignant
- Risk: fair skin, blue eyes, red/blond hair, outdoor occupation, older age, childhood freckling
round to dome-shaped mobile lesion that contains expressible material
cysts
-usually flesh colored papule or nodules
-can become inflamed infected
Cyst tx
- Excise: surfical excision to remove cyst wall
- infected: Warm compress, incision and drainage, Antibiotics
Hair growth phases
-Anagen: actively growing
- Catalan: involuting hair
- Telogen: resting hair
hypertrichosis
excessive hair male/female
hirsutism
female, male pattern hair growth
alopecia
-too little hair
scarring: loss follicular openings on scalp
- non scarring: follicular openings preserved
alopecia areata
-idiopathic disorder that is T-lymphocyte mediated
- patients usually healthy
- acute onset
tx: steroids, calcineurin inhibitors, immunotherapy
androgenetic alopecia
-dependent androgen receptors and 5-alpha reductase
-Tx: Finasteride (men), spironolactone
Piebaldism
- at birth, AD
KIT Gene
loss of melanocytes (fail to migrate)
part of hair white
Oculocutaneous albinism
-defect melanogenesis, melanocytes present but decreased pigment
-ocular manifestations
- risk of skin cancer
* lack of tyrosinase
depigmented macule from loss of melanocytes
vitiligo
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