Dermatology Lecture 2 pt 1 Flashcards
What are 4 types of insects/parasites we covered in this presentation?
Lice
Bedbugs
Scabies
Spider bites
What is this parasite and what are the 3 types?
Pediculus humanus capitis (head louse)
- Pediculus humanus corporis (body louse, clothes louse)
- Pthirus pubis (“crab” louse, pubic louse)
How do lice give us pruritus?
Pruritus occurs as an allergic reaction to lice saliva injected during feeding
What is the first line treatment for lice?
Topical insecticides such as permethrin or pyrethrin. Ivermectin 2nd line
reapplication 7-10days to kill newly hatched lice
Nit combing
Disinfection or disposable of clothing, bedding, grooming supplies
What condition? When do they feed?
Bed bugs. Feed at night on blood
What type of rash do bed bugs produce?
-See macular popular rash with central
scab and moderate pruritis
- 2-5 mm erythematous papule or wheal with
central hemorrhagic punctum
Treatment for bedbugs?
Get rid of source of bedbugs. Expensive cleaning of the home.
Tx is symptomatic
What condition is this? Describe it
Scabies
Pruritic burrows, vesicles, and or nodule with excoriations and crusting
What are scabie infections commonly located?
Between fingers, wrists, flexor aspects and waistline.
How are scabies spread? Situations where commonly acquired?
Spread by prolonged skin to skin contact
* Frequently sexually acquired
* Common in crowded conditions
* Exposure to clothing, bedding, furniture used by an infested person
Clinical features and symptoms of scabies?
May take up to 2 mos before S/S appear
- Infested but asymptomatic person can still transmit scabies
- Intense itching, usually worse at night
- Papular rash
- Burrows
- Areas of predilection:
—- Finger web spaces, Wrist, Elbow, Axillae, Penis, Nipples, Waist, Buttocks - Infection always a concern with intense scratching (MRSA, fungus)
What type of infection?
Scabies
What is the treatment for scabies?
Permetherin 5% Cream (Elimite)
* Apply to entire body from neck down
* Leave on for 8 hours then shower off
* Repeat the treatment just in case
- 48 hrs after first application (time interval varies)
- Can be used @ 2 mos old
What are non-pharmacological treatment considerations for scabies?
What is a condition that can develop in people that are immunocompromised that get infected with scabies?
What are the two most concerning types of spider bites?
Brown recluse and black widow
What spider is this? Where is it found?
Brown Recluse
Found in southern and midwestern US
Usually not aggressive
Hide in dark places:
–Rocks, logs, caves, closets, garages, attics
How is a severe brown recluse bite described?
The lesion is a sinking macule, pale dead gray in color, slightly eroded in the center, with a halo of very tender inflammation and hemorrhage
Describe minor brown recluse bites and what are mc location of bites?
Most bites are minor
* Erythema and edema
* Envenomation can cause tissue necrosis and hemolysis
MC location: arms, neck, lower abdomen
Describe the typical brown recluse bite?
Painless or stinging sensation initially
- Within a few hours site is painful and pruritic
- Central induration with a zone of ischemia and zone of erythema
- In most cases resolves in a few days without tx
What condition is this?
Minor Brown Recluse bit
Describe a severe brown recluse bite and wound progression
- Spreading erythema with center of lesion becoming hemorrhagic and necrotic
with overlying bulla - Black eschar forms and sloughs weeks later leaving an ulcer and eventually a
depressed scar (not that common) - Can result in nerve injury and secondary infection
- DEBRIDEMENT AFTER FULLY EVOLVE
What type of condition is this?
Severe Brown recluse bite
What are systemic complications of Brown Recluse Spider bite?
Fever, chills, weakness, HA, n/v myalgia, arthralgia, rash, leukocytosis may
develop <72 hrs after bite
- Rare-hemolytic anemia, hemoglobinuria, renal failure
Treatment for Brown Recluse bite
- Clean the wound, cold packs, elevate
- Pain relief
- Antibiotics if indicated
- Tetanus update
- Debridement/Skin Grafting (extensive debridement has not been proven
beneficial) - Monitor for signs of secondary complication
Black Widow Spider locations?
South Eastern US
Spin their web in dark places
* Under rocks, logs, barns, garages, outhouses
* Problem occurs when the web is disturbed or when spider is trapped
* Bites more common in summer or early autumn
Black Widow spider bites
Transmits strong neurotoxin
- The active component of the venom depletes neurotransmitters
Black Widow spider bite symptoms
The Black Widow cause neurologic overstimulation (muscle aches,
spasms, and rigidity)
- Painful cramps spread from bite site to large muscles of trunk and extremities
within 60 minutes - Extreme rigidity and intense pain of abdominal muscles
- Pain usually subsides within 12 hours, but can return
- Other symptoms, tachycardia, diaphoresis, vomiting, weakness, hyperreflexia,
urinary retention, uterine contractions
Severe complication of black widow bites?
- Complications-Renal failure, respiratory arrest, cardiac failure, cerebral
hemorrhage. These occur in the elderly, young, and sick
Treatment for black widow spider bites?
- Clean wound
- Tetanus
- Analgesics
- Antispasmodics (Benzodiazepines, Calcium Gluconate)
- Anti-venom for moderate to severe bites unresponsive to care. Rarely
indicated and not readily available
What are 4 hair and nail conditions we talk about in this section?
Alopecia Areata
Androgenic (genic) Alopecia
Onychomycosis
Paronychia
What condition is this ? How is it defined?
Alopecia areata
It is a chronic, relapsing, immune-mediated, inflammatory disorder that affects hair follicles and results in nonscarring hair loss.
Describe the presentation of Alopecia areata?
Circular/patchy (areata) shape
Sharply outlined portion (unlike fungus condition) of the scalp with complete hair loss, without erythema, scale, atrophy, or scarring
Can be seen with SLE
What are the 3 types of Alopecia?
- Alopecia Areata- Discrete patches of loss
- Alopecia Totalis- Entire scalp is bald
- Alopecia Universalis- All hair bearing areas of body are bald
What is the general definition of Alopecia areata?
Recurrent non scarring alopecia that can affect any hair bearing area
* Scalp, beard, eyebrows
* Localized<50%, Extensive>50% involvement
What are the causes and clinical features of Alopecia areata?
Cause is unknown but believed to be autoimmune/genetic
-Clinical features
* Pt usually asymptomatic
* Possibly mild pruritis or burning
* Discrete bald patch with smooth non inflamed underlying skin
* Exclamation hairs are pathognomonic
What is this condition?
Alopecia areata
What clinical feature of alopecia areata is this picture demonstrating?
What is the diagnostic evaluation for Alopecia areata?
- Pull test-Pull from the periphery of patch. If hair easily pulls out disease is
active and more loss can be expected - Dx made clinically
- Association with other diseases
- Thyroid testin
What is treatment options for alopecia areata?
- Depends upon extent of disease
- Topical or intralesional steroids
- Immunotherapy
Discuss treatment outcomes of alopecia areata?
- Wigs or hair prosthesis
- Disease is unpredictable
- Chance of regrowth great with limited dz, worse chance with extensive dx
- When hair regrows it will be white and fine
- No preventative tx
- Psychosocial suppor
What are other conditions that present similarly to Alopecia?
What is androgenetic alopecia?
Genetically determined patterned alopecia
- Affects men and women
- Progressive
- What occurs is a gradual conversion of terminal hairs to
indeterminate hairs to finally vellus hairs, “miniaturization” - Disease of cosmetic concern
- Female pattern hair loss for women
General symptoms of androgenetic alopecia? How does it progress in men vs women?
- Patient may report increased hair shedding
-No pruritus or inflammation present
-Men tend to present with gradual thinning at temporal hairline
——* Gradual frontal recession
Women tend to present with thinning at crown of scalp. Women may notice widened part
What is this a picture of?
Hamiliton-Norwood scale
Shows progressive balding occurring from bitemporal recession, to frontal and/or vertex thinning to loss of all hair except for occipital and temporal margins.
What is this a picture of ?
Ludwig scale
How to diagnosis androgenetic alopecia?
- Labs- Hormonal testing for females (DHEAS and testosterone)
- Scalp biopsy-need 2 samples for both horizontal and vertical sectioning
Treatment for androgenetic alopecia?
- No cure
- Any tx is attempt to maintain not regrow
- Regrowth is possible not guaranteed
- Best to tx early
- Minoxidil (Rogaine)-Topical soln
- 2% and 5% strengths
- Finasteride (Propecia)-Oral medicine
—–* Not for use in females-teratogenic and can produce feminization in male fetus - Spironolactone for females
Topical minoxidil MOA and ADR?
Oral Finasteride MOA and ADR
Non-pharmalogical treatments for androgentic alopecia?
- Surgical Treatment:
- Hair transplant
- Wigs
- Course is unpredictable