Dermatology Flashcards
(38 cards)
Bullous pemphigoid
antibodies to hemidesmosomes (connect basal keratinocytes to basement membrane in basal layer of epidermis)
Pemphigus vulgaris
antibodies to desmosomes (connect keratinocytes to each other in epidermis)
Xeroderma pigmentosum
AR genetic disorder in which the pt has ineffective DNA repair mechanisms; results in several base cell carcinomas, malignant melanomas, and squamous cell carcinomas in XP pts who are exposed to sunlight
Hypohidrotic ectodermal dysplasia
thermoregulation disorder:
mutation in EDAR gene (protein for proper interaction btw developing ectoderm and mesoderm) results in an inability to regulate temperature, so these pts overheat easily, and also have abnormal hair follicles, sweat glands, and teeth
What are the 3 layers of the skin and their resident cells?
Epidermis - keratinocytes, melanocytes, Langerhans cells, Merkel cells
Dermis - fibroblasts, collagen, elastic, blood vessels, nerve endings
Subcutis - fat, blood vessels, fibrous septae
What are the 4 layers of the Epidermis and their resident cells/materials?
BOTTOM - stratum basale/basal layer, stem cells that give rise to new KCs
Next up - stratum spinosum, where the cells differentiate and appear spiny because of the visible desmosomes connecting the KC to each other; also has lamellar (lipid) granules for barrier function
Almost to the top - stratum granulosum, where the cells appear granular because they are synthesizing the IC keratohyaline granules; also here the lamellar granules are secreted into the ECM for water barrier
TOP - stratum corneum, where the cells are flat and function as the barrier-most layer where keratins and filaggrins create protective layer and keep water in the cells
Melanocytes
melanin (pigment) -producing dendritic cells derived from neural crest; located among the basal cells in the epidermis, about 1MC:10KCs
Langerhans cells
Dendritic cells (APCs) in mid-epidermis; they recognize antigens, phagocytose, process, and present to LCs in regional lymph nodes
Merkel cells
epidermal cells associated with light touch sensation
Apocrine vs. Eccrine sweat glands
Apocrine glands are associated with hair follicles, component of the pilosebaceous unit
Eccrine glands are the “true” sweat glands that open directly onto the skin (not associated with hair follicle)
Epidermolysis Bullosa Simplex
genetic mutation in keratin 5 or 14; causes blistering and basal KC fragility, so the KCs break off when they should be attached by keratins to the hemidesmosome plate
Psoriasis
- long-lasting autoimmune disease characterized by patches of abnormal skin that are typically red, itchy, and scaly.
- etiology unknown but believed to be based in genetics, chronic infections, HIV, or drug-induced
- highly associated with metabolic syndrome, CVD, and obesity
Toxic epidermal necrolysis
often drug-induced, acute (dermatologic emergency) necrosis and sloughing of the epidermis
Atopic dermatitis
inflammatory condition of the skin that results in itchy, red, swollen, and cracked skin; cause is not known but believed to involve genetics, immune system dysfunction, environmental exposures, and difficulties with the permeability of the skin
Tx algorithm for acne
Mild comedonal: Top. retinoid
Mild inflammatory/mixed: Top. retinoid + top. abx
Moderate inflammatory/mixed: top. retinoid + top. abx + oral abx
Severe inflammatory/refractory to treatment:
minimal scarring: top. retinoid + top. abx + oral abx
scarring/multiple tx failures: Isotretinoin
Topical combos: Tretinoin + clindamycin
Adapalene + benzoyl peroxide
Tx for Rosacea
Topical:
Metronidazole, Azelaic acid, Sodium sulfacetamide w/ sulfur
Systemic:
Oral Tetracyclines
Other options for tx: IPL, Laser, Surgery
Tx for perioroficial dermatitis
Discontinue all topical steroids
Mild: Topical Abx
Severe: Oral Abx - may require topical NSAID
Folliculitis
Causes: bacterial- S. aureus, Streptococcus, Pseudomonas
fungal- Pityrosporum orbiculare
mite- Demodex folliculorum
Tx: Abx soap/wash
Top. Abx
Top. antifungal
Hidradenitis Suppurativa
Suppurative abscesses found in the axilla/inframammary folds and pannus of fat women who smoke.
Gaping holes in skin that leak nastiness.
Treat mild cases w/ topical or oral Abx
Treat moderate/severe cases with IL steroids, TNF-a inihibitors, surgery
Herpes Simplex Virus
Primary, latent, recurrent
HSV-1 = Above waist herp (85% seropositive)
HSV-2= below waist herp (25% seropositive)
dsDNA
Direct contact (3-7 day incubation before prim. infection)
Latent inf. travels to ganglia via sensory nerves.
Viral shedding in saliva/genital secretions
Prim. infection: burning, tingling, pain, fever, malaise, LAD
Recurrent inf.: tends to be milder
Triggers of flare: fever, sun exposure, stress (?)
Clinical pres: clusters of monomorphic vesicles, “punched out” erosions & crusted papules
Confirm Dx w/ Tzanck smear - look for multinucleated giant cells. Also viral culture & PCR.
Tx: mild- topical antiviral severe- oral or IV antiviral
Herpes Zoster Virus (VZV [varicella zoster virus])
Cause shingles- reactivation of latent infection
Up to 30% lifetime risk of shingles. More common after 60yo & immunosuppressed pts
dsDNA
Hangs out (latent) in dorsal root ganglia
Triggers: trauma, stress, fever, radiation, immunosuppression
Clinical: Prodrome- pain, itching, burning
Grouped vesicles over a dermatome
Trunk most common
Lesions at tip of nose (V1) - Hutchinson’s sign (nasociliary branch) could lead to blindness
V2/3- facial palsy, ertigo, deafness
Rash resolves 3-5 wks
Postherpetic neuralgia in 5-20% over 40yo
Confirm Dx w/ Tzanck smear, viral culture, PCR
Tx w/ oral antivirals within 72 hrs
Vaccine Zostavax for pts
Molluscum Contagiosum
Cutaneous infection caused by Pox virus
dsDNA
generally skin-skin contact. can autoinoculate, fomite.
resolves spontaneously
pink-skin colored, dome-shaped, waxy papules
+/- central umbilication
May cause mulluscum dermatitis (itchy rash)
Can occur anywhere on body
Can be confused for acne or folliculitis (look for comedones)
Tx- nothing really works well.
live with it.
curettage
cryotherapy
cantharidin (topical vesicant) 90% clearance after 2 appl.
Immunomodulators (Imiquimod- stim. TH1 cells to fight infection, cimetidine- blocks H2 receptor of T-cell repressor cells)
Retinoids, keratolytics
Warts
HPV
Take time to Tx
dsDNA
more than 100 serotypes
Appear anywhere
Benign, involute, can be painful
Can be oncogenic (16, 18, 31, 33)
Trans: contact, autoinoculation, fomite (don’t share towels w/ warty ppl)
2/3 resolve within 2 yrs w/o tx
Verrucae vulgaris- common wart
Verrucae plantaris- foot wart (pts hate these)
Verrucae plana- flat wart (face) shaving spreads
Condylomata acuminata- anogenital warts
Clue to Dx- parring reveals black dots
No good Tx. By all means, put some duct tape on your butthole.
But…immunomodulators & destructive methods may be implemented by physician
HPV vaccine
Gardasil (protects against serotypes 6, 16, 18, 11)
Cervarix (protects against 16 & 18)
preventing infection reduces risk of cervical cancer and mouth/throat cancers in males & females.
