Lice, Scabies, Spider Bites

Question 1

Pediculosis

1. What are they?
2. What is head lice called?
3. What is body lice called?

Answer 1

1. Ectoparasites that live on the body and feed on human blood after piercing the skin.
2. Pediculosis capitus: head lice
3. Pediculosis corporis: body lice

Question 2

Pediculosis
Clinical presentation?
3

Answer 2

1. Pruritus
   - May take 2-6 weeks to develop after first exposure
2. Itching and scratching can lead to secondary cellulitis
3. Pubic lice should prompt evaluation for other sexually transmitted infections

Question 3

Pediculosis

Dx? 3

Answer 3

1. Observation of:
   Eggs (nits)
   Nymphs
   Mature lice
2. Commonly found behind ears and on the back of the neck
3. Wood lamp of area
   Yellow-green fluorescence of lice/nits

Question 4

Pediculosis Treatment

1. Medication: Focus on two mechanisms? (which drugs go with these mechanisms?)

Answer 4

Medication
Focus on 2 mechanisms
1. Neurotoxicity
-Permethrin 1% lotion (Nix) first-line
2. Suffocation via “coating”
-Benzyl alcohol 5% lotion (Ulesfia)

Question 5

Which drug promotes hyperexcitation and death by paralysis?

Answer 5

Spinosad 0.9% (Natroba)

Question 6

Environmental control

Treat all persons who have contact with infested patients (especially who?

Answer 6

Sexual partners

Question 7

Sarcoptes Scabiei (Scabies)
1. What is it?
2. How do we find them?
2

Answer 7

1. Contagious infection caused by the mite Sarcoptes Scabiei.
2. • Tiny and usually not directly visible
   • Parasite that burrows under the host’s skin causing intense itching

Question 8

Sarcoptes Scabiei (Scabies)

1. May be transmitted from _____?
2. Most often transmitted by what?
3. Spread rapidly under crowded condition such as? 4
4. Usually symptomatic after how long?

Answer 8

1. May be transmitted from objects
2. Most often transmitted by direct skin to skin contact

Higher risk with prolonged contact

3. Spread rapidly under crowded conditions
   - Nursing homes
   - Extended care facilities
   - Prisons
   - Child care facilities
4. Usually two to six weeks before become symptomatic

Question 9

Sarcoptes Scabiei (Scabies)

1. Common sites of mites?
2. Common sites of rash? 7

Answer 9

1. Creases in skin
2. • Axilla
   • Stomach
   • Genitals
   • lower back/buttocks
   • elbows
   • knees
   • upper back

Question 10

Sarcoptes Scabiei (Scabies)
Classic scenario:

Itching:

1. Caused by what?
2. May be worse with what?
3. Worse when?
4. Watch for what?

Answer 10

1. Caused by allergic reaction to the mites.
2. Made worse by warmth
3. Usually worse at night
4. Watch for excoriation

Question 11

Scabies
Types of lesions?
5

Answer 11

1. Burrow- linear tunnel in which the mites live
2. Papules
3. blisters
4. nodules
5. eczematous

Question 12

Scabies
Dx?
2

Answer 12

1. Scraping off a tiny bit of skin

2. View under a microscope for mites or eggs

Question 13

1. Scabies treatment
2. Apply where?
3. Leave on for how long?
4. Repeat when if necessary?
5. Safe for children as young as what?
6. SE? 4
7. Treat who else? 2

Answer 13

1. Permethrin Cream 5% 60 gram tube (preferred treatment)
2. Apply from head to feet
3. Leave on for 8-14 hours then wash with soap and water
4. Repeat in 7 days if necessary
5. Safe for children as young as 1 month old and pregnancy
6. Side effects:
   - Mild to moderate burning and stinging
   - Itching
   - Rash
   - Redness
7. Treat family members and sexual partners

Question 14

Scabies treatment

Alternate medications? 2

Answer 14

1. Lindane Lotion 1%

2. Oral Ivermectin

Question 15

Lindane Lotion 1%

1. Disadvantage?
2. Most pts require what?

Oral Ivermectin

1. Dosing?
2. Do not use in who? 2

Answer 15

Lindane Lotion 1%

1. Has more neurotoxicity than Permethrin
2. Most patients require 30ml but larger adults up to 60ml

Oral Ivermectin

1. 200mcg/kg by mouth as single dose with repeat dose in two weeks
2. CDC recommends not using in pregnant or lactating women

Question 16

Scabies
Can give something for the itching? 3

Watch for what?

Answer 16

1. Atarax (Hydroxyzine) 10-25mg po every 4-6 hrs prn itching
2. Benadryl 25mg po every 4-6 hrs prn itching
3. Steroid cream

Secondary infections

Question 17

1. How do spiders cause infection?

2. Which spiders are most likely to inflict medically significant bites? 2

Answer 17

1. Use sharp fangs to bite prey and inject venom

Spider bites:
Rare medical events
Most pose no threat to humans

2. Spiders most likely to inflict medically significant bites
   - Widow
   - Recluse

Common disorders can mimic a spider bite

Question 18

1. How do widow spider bites look?
2. What do they release?

Recluse

3. Notorious for becoming what?
4. What kind of reaction do they cause?
5. What toxin do they release?
6. Genus?

Answer 18

1. Unremarkable local lesions
   - Characteristic systemic reaction
2. Neurotoxin
   α- latrotoxin
3. Notorious for becoming necrotic (rare)
4. Systemic reaction mild
   - Nonspecific signs and symptoms
5. Sphingomyelinase D
6. Latrodectus genus

Question 19

Spider bites: Acute lesions can be what? 3

Answer 19

1. Papule
2. Pustule
3. Wheal

Question 20

Widow spiders
Patient History
Recent less than 8hrs at risk activity
5

Answer 20

1. Gardening
2. Chopping wood
3. Using outdoor furniture
4. Cleaning a garage
5. Moving into a house that has not been occupied recently

Question 21

Widow Spiders History findings?

3

Answer 21

1. Bite usually on the extremities (especially lower)
2. Most are initially asymptomatic or cause mild pain at the site
3. Muscle pain is the most prominent feature in systemic reactions

Question 22

Muscle pain is the most prominent feature in systemic reactions.
How does it manifest?
3

Other symptoms may include? 3

Answer 22

1. Extremity muscles
2. Abdomen
3. Back
4. Tremor
5. Weakness
6. Shaking of the extremity

Question 23

Presentation of infants and children for widow bites?

4

Answer 23

1. Nonspecific
2. Distressed and inconsolable
3. Refusing food and drink
4. Generalized erythema

Question 24

Widow bites: Physical findings?

5

Answer 24

1. Vital signs normal in 70% of patients

Musculoskeletal exam:
2. Intermittent muscle rigidity and

3. tenderness adjacent to the bite
   OR abdomen, chest or back
4. Weakness, tremor, and myoclonus
5. Diaphoresis:
   Corresponds to affected muscle group

Question 25

Widow Physical findings: Wound site & local symptoms 5

Answer 25

1. Blanched circular patch 2. Surrounding red perimeter 3. Central punctum 4. Appears like a “target” lesion - 50 percent of cases

Question 26

Widow bite Dx 1. Primarily based on what? 2. Possible lab studies? 3 3. Adults with cardiac risk factors consider? 2

Answer 26

1. Primarily based on symptoms and signs with history 2. No specific lab studies - Leukocytosis - Elevated creatinine - Elevated Liver enzymes 3. Adults with cardiac risk factors consider: - EKG’s - Cardiac enzymes

Question 27

DDx for Widow bites? 6

Answer 27

1. MRSA 2. Surgical abdomen 3. Lyme 4. Myocardial ischemia or infarction 5. Tetanus 6. Rabies

Question 28

Envenomation Mild presentation? 2 Moderate presentation? 4 Severe? 3

Answer 28

Mild 1. Localized pain at bite 2. Normal vital signs Moderate 1. Muscular pain in envenomated extremity 2. Extension of muscular pain to chest or abdomen 3. Local diaphoresis at bite 4. Normal vital signs Severe 1. Generalized muscular pain in back, abdomen and chest 2. Diffuse diaphoresis 3. Abnormal vital signs

Question 29

Mild Envenomation treatment? | 4

Answer 29

1. Local measures: Gently clean the bite with mild soap and water 2. Oral analgesia: 3. Oral muscle relaxers: 4. Tetanus prophylaxis if indicated

Question 30

Mild Envenomation treatment: 1. What would you use for oral analgesia? 3 2. What would you use for oral muscle realxers? 2

Answer 30

1. - Acetaminophen - Ibuprofen - Oxycodone or hydrocodone 2. - Benzodiazepines (Valium) - Methocarbamol (Robaxin)

Question 31

Moderate to Severe Envenomation treatment? | 5

Answer 31

1. Local wound care and tetanus prophylaxis as for mild envenomation 2. Parenteral opioids (e.g. morphine) 3. Parenteral benzodiazepines (e.g. lorazepam) to reduce the frequency and severity of muscle spasms 4. Antiemetic therapy (e.g. Sublingual or intravenous ondansetron) 5. Consider Antivenom administration - Consult with medical toxicologist prior to administration - Carries small risk of anaphylactic reactions

Question 32

Brown Recluse 1. Where do you usually sustain the bite? 2. Typically appear where? 3 3. Notorious for what? 4. FOund where? 3 5. Produces what? 6. Genus?

Answer 32

1. Bites are usually sustained indoors 2. Typically on - upper extremities, - thorax or - inner thigh 3. Notorious for sometimes causing skin necrosis 4. South, West, and Midwest areas 5. Cytotoxic enzymes 6. Loxosceles

Question 33

1. Brown recluse local symtpoms? 4 | 2. Systemic? 4

Answer 33

Local Symptoms: 1. Usually develop two to eight hours after a bite. 2. Usually painless initially 3. Occasionally some minor burning that feels like a bee sting 4. Severe pain at bite site after about four hours Systemic symptoms: 1. Malaise 2. Nausea & Vomiting 3. Fever 4. Myalgias

Question 34

Brown Recluse physical findings? | 5

Answer 34

1. Initially bite site is mildly red 2. May reveal fang marks 3. Blistering (common) 4. Necrosis of skin and subcutaneous fat (less common) 5. Severe destructive necrotic lesions with deep wide borders (rare)

Question 35

Brown Recluse Dx? Based on? 2 Definitive Dx? 2 If both these conditions are not met what must you do?

Answer 35

1. Based most often on: - History - Clinical presentation 2. Definitive: - A spider was observed inflicting the bite - Spider recovered, collected, and properly identified by an expert entomologist 3. If both conditions are not met, then other conditions must be excluded.

Question 36

Brown Recluse DDx? | 10

Answer 36

Numerous conditions mistaken for recluse spider bite 1. Bacterial 2. Deep fungal 3. Pseudomonas aeruginosa 4. Parasitic 5. Viral 6. Topical and exogenous causes 7. Venous 8. Neoplastic disease 9. Necrotizing vasculitis 10. Diabetic ulcers

Question 37

Brown recluse treatment | 5

Answer 37

1. Local wound care 2. Pain management with NSAIDS or opioids if necessary 3. Tetanus prophylaxis if indicated 4. Dapsone in some cases to prevent progression to necrosis & reduce pain 5. No Antivenom available in the United States

Question 38

What would you do for local wound care for a brown recluse? | 3

Answer 38

1. Clean with mild soap and water 2. Apply cold packs 3. Maintain affected part in elevated or neutral position