Dermatology #2 Flashcards
Pityriasis Rosacea is associated with what?
Human herpesvirus 7
Describe the symptoms of Pityriasis Rosacea
-Viral Prodrome
-Herald Patch (solitary salmon colored patch on trunk)
-Pruritic papules in Christmas tree pattern that follows cleavage lines on trunk
Lichen Planus is an immune related condition that is associated with
Hepatitis C infection
Describe the rash of Lichen Planus
6 P’s
-Pruritic, Purple, Planar (flat), Polygonal (irregular), Papules, Plaques (Raised)
-Wickham Striae: white lines on skin or oral mucosa
-Koebner’s Phenomenon: new at sites of trauma
-Nail dystrophy
Where are the three areas the lichen planus affects MC?
Wrist, ankles, mouth
Treatment for lichen planus
Topical corticosteroids; however, most resolve spontaneously over 8-12 months
What are three common culprits of fixed drug eruptions?
NSAIDs, Antibiotics, Antiepileptics
MC pre-malignant skin condition
Actinic Keratosis
Actinic keratosis is the ____________ and risk factors include _____, ____, and ______
proliferation of keratinocytes
Sun exposure, male gender, and increased age
Symptoms of actinic keratosis
Dry, rough sandpaper like papules with transparent or yellow scaling
What test should be done for actinic keratosis and why
Punch biopsy to determine if AK or SCC
Treatment for AK
-Localized: liquid nitrogen cryotherapy
-Multiple: Topical 5-FU and Imiquimod
The MC benign epiderma tumor
Seborrheic keratosis
Seborrheic keratosis is the __________ and looks like
benign proliferation of immature keratinocytes
Velvety, warty, stuck on appearance
MC etiology of onychomycosis
T. Rubrum
Symptoms of onychomycosis
-Opaque nail, thickened, discolored
-MC on great toe
Diagnostics for onychomycosis
-Fungal culture and rapid test (KOH prep) before treatment
-Periodic acid-schiff test (most sensitive)
First line treatment for onychomycosis and two contraindications to using this medication
Terbinafine
-Hepatitis and Alcohol use (hepatotoxicity)
MCC of a paronychia
Staph A
What is a paronychia
Infection of the lateral and proximal nail folds < 6 weeks
Etiology of a paronychia (why does it occur?)
Nail biter: normal oral flora
Treatment for paronychia
-Mild: warm water soaks
-Moderate: Oral Cephalexin or Dicloxacillin (Clinda or Aug if nail biter)
-MRSA: Bactrim, Clinda, Doxy
A paronychia can progress to a _______, which has symptoms of fluctuant of the pad of the fingertip. What is the treatment?
Felon
Incision and drainage, Cephalexin afterwards
Alopecia Areata is immune mediated and targets _____ hair follicles. What are some symptoms of this type of alopecia?
Anagen
Exclamation point hairs: tapering near proximal hair shaft
Nail abnormalities: pitting, fissuring, roughening
Treatment for alopecia areata
Intralesional corticosteroids
The MC type of alopecia in both genders is _______. Explain the difference in distribution of this condition among genders
Androgenic alopecia
Males: bitemporal thinning –> vertex
Females: between frontal and vertex of scalp
What is the pathophysiology of androgenic alopecia?
DHT is the key androgen. It shortens the anagen phase (growth phase) in the normal cycle of hair.
What is seen on dermoscopy in a patient with androgenic alopecia?
Mini hair and brown perihilar casts
Treatment options for androgenic alopecia
-Topical Minoxidil: widens blood vessels
-Oral Finasteride: androgen inhibitor. Stops conversion of testosterone –> DHT
-Hair transplant
Treatment of choice for pediculosis (lice)
Topical Permethrin shampoo x 10 minutes
Remove nits with fine tooth comb
Wash bedding, clothes and dry them in high heat
Besides being a clinical diagnosis, what other thing can you use to diagnose pediculosis?
Wood’s lamp
What is one common adverse effect of Lindane, an alternative treatment for pediculosis?
Seizures
Do not give in pregnancy
Scabies is a mite infection due to what organism? The females burrow into the skin to lay eggs, feed, and defecate
Sarcoptes scabiei
Symptoms of scabies
-Pruritis at night
-Linear burrows on intertriginous zones (web spaces of fingers, scalp, toes)
-Red, itchy papules on penis, body folds
Treatment for scabies
Permethrin topical (8-14 hours before showering) Reapply 1 week later
If the patient has Norweigan Crusted Scabies, what is the treatment?
Oral Ivermectin
Although bed bugs have a painless bite due to anesthetic and then proteases break down tissue, how can you diagnose this?
Look for blood stained bedding
-Supportive treatment only
1 cause of death of envenomation
Bee stings
What type of reaction is a bee sting?
Type I immediate reaction (IgE local reaction)
Symptoms of a black widow spider bite
-Local symptoms (pain at site)
-Neurologic symptoms within 2 hours
-Muscle pain
-Spasms, rigidity, tachycardia, HTN
What does the rash look like in a black widow bite?
-Blanched circular patch with surrounding red perimeter and central target lesion
The venom of a brown recluse spider is
cytotoxic and hemolytic…can be necrotic
What does the rash or bite site look like in a brown recluse bite?
Erythema at site –> blanching due to vasoconstriction –> red halo for 24 hours –> hemorrhagic bullae –> eschar formation
What type of tick and what is the bacteria that causes Lyme Disease?
Borrelia Burgdorferi on the Ixodes Scapularis (deer tick)
What are the MC states where Lyme’s occurs?
Northeast (CT, MA, NY, NJ)
Symptoms of Lymes
-Erythema Migrans: bullseye rash
-Neurologic symptoms: CNVII nerve palsy (MC)
-AV Block (MC)
-Intermittent arthritis (knee pain)
Although Lyme is a clinical diagnosis, what can be done to prove this diagnosis?
ELISA (serologic testing) then Western Blot if positive
Treatment for Lyme
Doxycycline BID x 10-21 days
-Amoxicillin if a child or pregnant
However, if the Lyme disease is late or severe, what is the treatment?
IV Ceftriaxone (with nerve palsy or AV block)
Rocky Mountain Spotted Fever, MCC by _____, occurs in what states?
Rickettsia Rickettsii
Southcentral and Southeastern States
What are the two vectors for RMSF?
Dermacentor andersoni & Variablis
Explain the rash of RMSF
Petechial rash on wrists/ankles then spreads to trunk
Treatment for RMSF? If Pregnant?
Doxycycline (first line)
Chloramphenicol (if pregnant)
What is Ehrlichiosis?
Tick borne illness that infects and destroys WBCs
What is the etiology of Ehrlichiosis?
Amblyorama (Lone Star Tick)
True or False: the symptoms of Ehrlichiosis are nothing special. Malaise, fever, with no special rash.
True
Treatment for Ehrlichiosis?
Doxycycline
-Chloramphenicol (second line)
A peripheral smear can be done for Ehrlichiosis. What should be seen on it with this condition?
Morulae in WBCs
Mulberry shaped aggregates
Leukopenia
What is one thing to remember and keep in mind when considering weakness, malaise, and ataxia after a tick bite?
Tick Paralysis
-Remove the tick!
Explain the four degrees of sunburns
1st: local erythema, resolves in days
2nd: blisters, painful, resolves in 2 weeks
3rd: painless, dry, leathery
4th: to muscle/bone, amputation
What are some risk factors for skin cancer?
Fair skin, age, family history, sun exposure, sunburns, radiation, immunosuppression
