travel, known endemic areas, schools, animals/pets, local wildlife, pools/lakes/oceans, other geological areas (desert, mountains, etc), exposure to others
what to pay close attention to during the work-up
-Severe pruritus & rash
-Excoriations, small vesicles, pustules, burrows
-Interdigital spaces of hands & feet
-Proximal palms, wrists, elbows
-Umbilicus, axillae, areolae (?), penile shaft & scrotum (?)
-Usually spares the head & neck
scabies presentation/location
-Close physical contact x15-20 min w/ infested person
-Can transmit through infected bedding
*Facility-associated scabies is common
-Mostly in long-term care facilities
-Elderly & immunosuppressed
-Misdiagnosis common
transmission of scabies
Sarcoptes scabiei
scabies etiology
scalp, palms, soles
where can scabies be found in infants
-clinical
-Confirm by microscopy to visualize organism, ova, or feces
-Microscopic specimen is examined with tap water, mineral oil, or KOH
scabies diagnosis
-Kill mites
-Wash bedding & clothing at high temps
-Permethrin 5% cream
-PO Ivermectin (immunocompromised or crusted scabies)
-to control dermatitis (that can last for months): Triamcinolone 0.1% cream
treatment of scabies
Ivermectin single oral dose (200 micrograms/kg)
**In endemic areas, mass intervention with ivermectin is effective in controlling both scabies and associated bacterial infections
what is effective for resistant cases of scabies?
-Presents as thick flaking scale
-Areas contain millions of mites
-Very infectious
-Pruritus often absent
-Risk of superinfection w/ S. aureus (sepsis if untreated)
-Look for underlying cause: HIV, HLTV-1 &Iatrogenic immunosuppression
Hyperkeratotic "Crusted" Scabies
-flea bites
-bed bugs
differential dx for scabies
No, it can last months. Topical corticosteroids can used --> triamcinolone 0.1% cream
does successful scabies treatment completely cure pruritis?
Parasitic infestation of skin due to Pediculus humanus
pediculosis (lice)
Pediculosis capitis (head lice)
Pediculosis corporis (body lice)
Pediculosis pubis (pubic lice) "crabs
3 types of lice that parasitize humans
-Pediculosis capitis (head lice): Shared hats or combs, contact
-Pediculosis corporis (body lice): Overcrowded dwellings w/ poor hygiene facilities
-Pediculosis pubis (pubic lice) "crabs": May be sexually transmitted
lice transmission
-trench fever, relapsing fever, typhus in endemic areas
-Bartonella quintana: associated w/ trench fever in U.S. homeless population
what can lice cause?
crawling sensation, itching. hair crusting
clinical manifestation of lice
-Intense pruritus, scratching, deep excoriations
-Visible lice or nits
-Pyoderma (overlying skin infection) may be presenting sign
lice presentation
back of the head and neck and behind ears. sometimes eyelashes. itchy bumps on nape of neck
PE for head lice (P. capitis)
adult lice and nits in clothing seams.
uninfected bites are red papules 2-4 mm in diameter with red base
PE for body lice (P. corporis)
lice in pubic hair and may spread to hair around anus, axillae, chest
PE for pubic lice (P. pubis)
-Clinical diagnosis made by visual inspection
-Nits are easiest to see above ears & at nape of neck
-Check seams of clothing
dianosis of lice
-Head lice: Seborrheic dermatitis
-Body lice: Scabies, bedbugs
-Pubic lice: Anogenital pruritus, eczema
differential dx of lice
-OTC 1% Permethrin cream rinse (Nix) preferred
-1% Malathion lotion (effective, but highly volatile & flammable)
-0.5% Ivermectin lotion
-Treat everyone infested at same time (family, school)
-Eyelid involvement - Apply thick petrolatum, pluck off remaini
treatment of pediculosis capitis (head lice)
OTC 1% Permethrin cream rinse (Nix) preferred
________________ is the preferred treatment for lice HOWEVER resistance is common
-Dispose of infested clothing
-Address patient's social situation
treatment of pediculosis corporis (body lice)
-1% Permethrin rinse OR 5% Permethrin cream
-Tx sexual contacts
-Wash & dry clothes at high temp
treatment of pediculosis pubis (pubic lice)
Bedbugs
Fleas
Mosquitoes
Biting flies
Chiggers
arthropods that may cause allergic reaction
Clusters of bites
Pruritus
Urticaria
Papules may become vesicular
*may have secondary bacterial infection after scratching
arthropod bites presentation
clinical
*hx is important
arthropod bites diagnosis
Topical corticosteroid (itching)
Topical antibiotics if 2� infection suspected
+/- Intralesional corticosteroids for persistent localized lesions
treatment for symptomatic arthropod bites
treat home & pets
treatment for flea bites
-aggressive cleaning
-antihistamines
-topical corticosteroids
-permethrin does NOT work for bed bugs (they can survive up to a year w/o feeding)
treatment of bed bugs
-Avoid contaminated areas
-Maintain personal cleanliness
-Disinfect clothing, bedclothes, furniture as needed
-Apply permethrin to head & clothing to repel chiggers & mites
prevention of arthropods
-Enterobius vermicularis (pinworm)
-Common worldwide
-Most prevalent in school-aged children
etiology of pinworms
-Person-to-person transmission
-Ingest eggs after contact w/ hands or perianal region of infected patient
-Food or fomites contaminated by an infected individual
-Infected bedding or clothing
how are pinworms transmitted?
-Eggs hatch in the duodenum and larvae migrate to the cecum
-Females mature in about a month and remain viable for about another month
-During this time, they migrate through the anus to deposit large numbers of eggs on the perianal skin
explain autoinfection of pinworms
-Most are asymptomatic
-Most common symptom is perianal pruritus (especially especially at night) --> due to the presence of the female worms or deposited eggs-Perianal scratching may cause excoriation & impetigo
-Insomnia, restlessness, & enuresis common
pinworm presentation
-Diagnosis made by finding adult worms or eggs on perianal skin
-Tape test is common: Apply clear cellophane tape to perianal skin, ideally in early morning � microscopic exam for eggs
-Nocturnal exam of perianal area may reveal adult worms
-Gross exam of
pinworm diagnosis
-Single oral doses of albendazole, mebendazole, or pyrantel pamoate --> Dose repeated in 2 weeks due to frequent reinfection
-Treat other infected family members concurrently
-Discourage perianal scratching
-Standard hand washing & hygiene practices to li
pinworm treatment
in wooded areas and animals. attaches to the skin and injects saliva. reaction consists of redness, pain and a papule
Bite is usually painless
tick bites
lyme disease- deer tick, Borrelia burgdorferi.
Rocky mountain spotted fever- dog tick, Rickettsia rickettsi
2 diseases caused by ticks
-Most common tick-borne disease in U.S.
-Northeast, mid-Atlantic, north central U.S
lyme disease
Host: White-tailed deer
Tick: Ixodes scapularis
Bacteria: Borrelia burgdorferi
Most infections in spring & summer
Tick must feed for 24-36h to transmit disease
? Infection risk if tick brushed tick off skin or removed day of exposure
**The engorged tick w
lyme disease etiology/host/tick/bacteria
...
preventing tick bites
-usually 1 week after tick bite
-Flat or slightly raised red lesion appears , expands over several days
-Commonly seen in areas of tight clothing such as the groin, thigh, or axilla
*Although originally described as a lesion that progresses with central c
erythema migrans
-Early localized infection
-Erythema migrans ? 1 week after bite
-Viral-like illness (myalgia, arthralgia, headache, fatigue, +/- fever)-->will likely resolves in � weeks on its own
stage 1 of lyme disease
-Early disseminated infection
-Up to 50-60% w/ erythema migrans are bacteremic
-Wide variety of transient viral S/S (days to weeks of original infection)
-Cardiac manifestations: Myopericarditis, with atrial or ventricular arrhythmias and heart block
-Neu
stage 2 of lyme disease
-Late persistent infection
-Months to years after initial infection
-Skin, neurologic, musculoskeletal manifestations (lyme arthritis)
**. The pathogenesis of chronic Lyme arthritis may be an immunologic phenomenon rather than persistence of infection.
stage 3 of lyme disease
fade within 3-4 weeks
how long do the lesions of lyme disease last?
Early disease = Clinical diagnosis
- Exposure in endemic area + erythema migrans
- Antibody titers if strong suspicion (may be negative if too early)
LATE DISEASE:
-Anti-Borrelia AB ELISA testing positive in 25% of pts
-use with Western Blot which is more
diagnosing lyme disease
-Doxycycline
-amoxicillin (if pregnant, lactating, allergy to doxycycline)
treating lyme disease
rocky mountain spotted fever. organism disseminates via bloodstream and multiplies in vascular epithelial cells
Vector: Wood tick (west coast), Dog tick (east coast)
Organism: Rickettsia rickettsii
*several hours of contact needed for transmission
**usual
RMSF etiology/epidemiology
typically Oklahoma and south Atlantic states
NC, TN, OK, MO, AR
where do you see RMSF?
- Symptoms occur abruptly 2-14 days after tick bite
- High fever, chills, headache, N/V, myalgias, restlessness, insomnia, irritability
-Rash between days 2-6 of fever
*Faint macules --> maculopapules --> petechiae
*Wrists & ankles --> spreads centrally t
clinical manifestations of RMSF
Rash between days 2-6 of fever
when does the RMSF rash begin?
Severe multiorgan dysfunction & up to 73% mortality rate if untreated
U.S. mortality rate for treated patients is 3-5%
The usual cause of death is pneumonitis with respiratory or cardiac failure
Mortality of RMSF
discrete, macular, blanches with pressure. petechial in 2-4 days.
RMSF rash
-Rash between days 2-6 of fever
*Faint macules --> maculopapules --> petechiae
*Wrists & ankles --> spreads centrally to arms, legs, & trunk over next 2-3d
*Palm & sole involvement is characteristic
where is the RMSF rash found?
spotless and occurs in 10% of pts. more common in adults
rashless RMSF
spleen (palpable on abdominal exam)
what may enlargen in RMSF?
clinical bc serological labs cannot confirm until 7-14 days after illness.
*Alternative: PCR of blood or skin biopsy
lab abnormalities: Thrombocytopenia, hyponatremia, elevated aminotransferases, hyperbilirubinemia, disseminated intravascular coagulation
diagnosis of RMSF
- Doxycycline
- Chloramphenicol if pregnant
-Fever usually breaks within 48-72h
-Tx continued for at least 3d after fever resolves
treating RMSF
Possible sequelae:
-Seizures
-encephalopathy
-peripheral neuropathy
-paraparesis
-bowel & bladder incontinence
-cerebellar & vestibular dysfunction
-hearing loss
-motor deficits
Possible sequela of RMSF
eggs can lay dormant for over a year. light pinching and short lived itching. clusters of itchy papules on the legs- usually grouped on ankles
fleas clinical manifestation
- Prophylactic Tx after a tick bite is not recommended
- No prophylaxis like in lyme disease
Is there a prophylactic treatment for RMSF?
red, raised urticarial lesions develop in hypersensitive patients, esp. children
papular urticaria
Honeybees/Bumblebees, Wasps, Yellow Jackets, Hornets and Ants (especially fire ants)
hymenoptera
Hymenoptera
**If allergy to one Hymenoptera insect, may have cross-sensitization to others
More fatalities from ____________ stings than stings or bites by any other insect
female
Males do not have a stinger.
Usually docile until provoked
A________ honeybee is capable of stinging only once because its stinger has multiple barbs that cause the sting apparatus to detach from the bee's body, leading to evisceration and eventual death.
�Venom has same toxicity as honeybee but are more aggressive
�Attack in swarms w/ many stings
�Can --> multisystem damage & death from severe venom toxicity
Characteristics of africanized "killer" honeybees
Wasps, Hornets, Yellow Jackets
*****Location of nests
Yellow jackets: Ground
Hornets: Trees & shrubs
Wasps: Walls
which hymenoptera are capable of multiple stings? location of their nests?
Wasps, Hornets, Yellow Jackets
Represents most allergic reactions among Hymenoptera order
-Inhabit loose dirt, breed 9-10 months out of a year
-Swarm when provoked & may attack in great numbers (alarm pheromone)
-Immobilized/elderly can become rapidly covered (severe stings or death)
Hymenoptera - Fire Ants Characteristics
- Immediate local reaction
- Wheal & pustule at sting site
- Followed by extension of edema, erythema, induration, intense pruritis
- Can rarely lead to urticaria, angioedema, anaphylaxis
- Rhabdomyolysis & renal failure possible after massive fire ant st
characteristics of fire ant stings
Organ System Effects
Renal and hepatic failure and disseminated intravascular coagulation can result from massive bee stings. Creatine phosphokinase concentrations can reach 100,000 IU/L or greater in cases in which rhabdomyolysis occurs from direct venom
Hymenoptera - Presentation
Admission or observation: Large numbers of stings, substantial comorbidities, & extremes of age
Hymenoptera treatment
minutes after sting. itching, hives, SOB, wheezing, abdominal cramps, shock, low BP, death
ANAPHYLAXIS in ant, bee, wasp stings
- small spider with violin markings on it and lives in dark and undisturbed areas
- Better identified by eye pattern (3 pairs instead of 4 pairs)
- Found in indoor & outdoor in dark dry areas
- Basements, closets, woodpiles
describe brown recluse spider aka Loxosceles reclusa
sphingomyelinase D. responsible for significant cutaneous injury with eventual tissue loss and necrosis (rare)
brown recluse toxin
SEVERE CASES: "Red, white, and blue" sign (erythema, blanching, ecchymosis)
Other s/s
�N/V, fever, chills, arthralgias
�Thrombocytopenia, rhabdomyolysis, hemoglobinuria, renal failure
�DIC & death are extremely rare
clinical manifestations of brown recluse bite
brown recluse bite
hemolysis is a major symptom of
children & occur 24-72h after bite
systemic effects of a brown recluse bite is seen more often in..
edema around bite produces a red halo around lesion. red margin gets bigger as gravity pushes venom through tissues. within 24-72 hours a single cyanotic or hemorrhagic vesicle develops at site and forms a dark eschar
brown recluse lesion for PE
�Treatment consists of mostly supportive care
-Many specific treatments studied show no benefit
- Most wounds are self limiting
- No commercially available antivenom in U.S.
- ABX if signs of infection (uncommon)
-Arrange f/u for serial wound evaluation
-
treating brown recluse bites
-Correct diagnosis without definitive spider I.D. is difficult
-If bite suspected & S/S of envenomation: Obtain CBC, BUN, creatinine, & coagulation profile
How is a brown recluse bite diagnosed?
Dapsone
what can prevent severe necrosis in brown recluse bites
- Orange-red hourglass shaped marking
- Worldwide distribution
- Highly potent venom (Mass release of acetylcholine --> neuromuscular manifestations & norepinephrine --> cardiovascular manifestations)
- Only females can penetrate human skin
LOCATION
Woodp
Characteristics of black widow aka Latrodectus
- Most bites are felt immediately as a pin-prick
--> Increasing pain, may spread quickly & include entire extremity
--> Erythema appears ? 20-60 min later
black widow bite presentation
- Local, regional, or generalized pain
- May be associated w/ systemic symptoms & autonomic effects
clinical manifestation of black widow bite
Acetylcholine release accounts for neuromuscular manifestations, and norepinephrine release accounts for the cardiovascular manifestations
- Cramp-like spasms in large muscle groups are common
- Often ? progressively, becomes generalized: trunk, back, & a
systemic manifestations associated with a black widow bite
small red circle around bite site. surrounded by area of blanching and outer halo of redness. looks like a target.
black widow lesion
...
Clinical diagnosis of black widow bite
- Clean bite site & manage pain (opioids, benzodiazepines)
- Admission may be necessary
Black widow treatment
Typical Progression
1. Pruritus, flushing, urticaria
2. Throat fullness, anxiety, chest tightness, SOB, lightheadedness
3. Respiratory distress, decreased level of consciousness, CV collapse
Typical progression of anaphylaxis
Clinical
- Involves ? 2 body systems w/ or without hypotension or airway compromise
Diagnosing anaphylaxis
Anaphylaxis
- Serious allergic reaction w/ rapid onset (usually w/i 6h)
- Most common reasons: Foods, meds, stings, allergen immunotherapy
Vasopressors
used in patients with anaphylaxis and shock resistant to initial treatment, including repeated doses of IM epinephrine, oxygen, and IV crystalloids
...
Anaphylaxis treatment
antihistamines
corticosteroids
EpiPen
After anaphylaxis occurs healthy patients who remain symptom free for 1-6 hours may be discharged with a rx for what?
nematocytes (specialized cell in the tentacles of a jellyfish containing a barbed or venomous coiled thread that can be projected in self-defense or to capture prey).
how do jellyfish inject venom?
Main jellyfish of human concern
- Portuguese man-of-war
- Bluebottle jellyfish
- Box jellyfish
- Jellyfish that cause Irukandji syndrome
Main jellyfish of human concern
...
Jellyfish sting presentation
- Irrigate (w/ seawater or NS) to remove & deactivate undischarged nematocysts
- Do not use regular water (fresh water)
- Remove remaining tentacles (scape skin w/ credit card or use tape)
- Hot water immersion - (111�F [43.3�C] to 114�F [45.6�C])
- Topic
general treating jellyfish stings
Physalia species
Portuguese Man of War and blue bottle jellyfish are part of the _____________
- Immediate intense pain (fades over an hour, may persist for many hours)
- Characteristic linear erythematous eruption "string of pearls" pattern
- Respiratory distress & death have been reported- rare
- Delayed effects reported in rare instances
Characteristics of Physalia sting
Treat as a general jellyfish sting - No antidote for Physalia envenomation
How to treat a physalia sting?
�Common in Florida, parts of Asia, Africa, Australia, Western Europe
�Swarms in shallow water --> stings in surf or washed ashore
Where is the physalia species located?
- The box jellyfish
-Indo-Pacific, Australia, Philippines, Japan, U.S. Atlantic coast, Hawaii
The most dangerous jellyfish
Tx for severe envenomation:
- Standard resuscitative measures
- Sheep-derived antivenom
- May repeat dose if no clinical response
- Hot water ineffective at treating
What is the treatment for the box jellyfish
- Most stings are mild-moderate (wheal, immediate severe pain)
- Severe reactions or death can occur (especially in children)
** death could be in 1-2 minutes
indo-pacific box jellyfish stings
Rapid onset wheals, vesicles, reddish brown or purple whip-like flare pattern w/ stripes 8-10 mm wide
Blistering --> superficial necrosis after 12-18h if severe
Pathognomonic crosshatched "frosted ladder" pattern if severe
Followed by a delayed hypersensi
Clinical presentation of indo-pacific box jellyfish
Australian Box jellyfish
Causes irukandji symdrome
- Initial mild localized pain & erythema
- 20-30 min later --> severe generalized pain in abdomen, back, chest, head, & limbs
- Pain usually associated w/ systemic signs of catecholamine excess
-In severe cases, cardiogenic shock w/ pulmonary edema & ? se
Clinical presentation of australian box jellyfish sting
brackish water and bays. fresh water in South America
where do you find stingrays?
stepping on the ray. tails has barbs that cause a laceration and envenomation- barbs left in the wound
sting ray exposure
�Cause immediate intense local pain
�May radiate and last for hours
�Often significant bleeding, depends on site of injury
�Systemic effects are uncommon & usually 2� to pain
clinical manifestations of sting rays stings
abx for vibrio coverage
treating sting ray stings
swimmer's itch
- Following skin penetration by cercariae of non-human schistosomes
cercarial dermatitis
intense itch where schistosome larvae of the Trematode worm parasite penetrate the skin. found in clear water, ponds, lakes around the world
swimmer's itch etiology
�Treatment is symptomatic (control pruritus)
�Rash typically clears within a few days
treating swimmer's itch
�Itchy maculopapular rash, limited to areas immersed in water
�Red papules that may become vesicular
�Develops over hours to 1-2 days
Swimmer's itch presentation