Dermatology IV: Infestations and Bug Bites – Flashcards
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infestations
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-pediculosis (crab lice/body and Head lice) -demodex -scabies
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bites
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-bed bugs -triatorminae/mites -fleas -assassin/kissing bugs -ticks -spiders -puss caterpillars -ants, bees, and wasps -mosquito and mosquito borne diseases
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etiology pediculosis
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-phthirus pubis (crab louse) -pediculosis humanus capitis -pediculosis humanus corporis
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etiology pediculosis humanus
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-contagious infestation in hairy areas of body or in cases of body lice, in the seams of clothing
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epidemiology pediculosis
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-prevalence is dropping -transmitted by close personal contact -cannot survive off body for longer than -10 days-adults -3 weeks- eggs
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subjective pediculosis pubis
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-moderate pruritus (itching) -rash reported (bites) -red dots (excrement) on lower lids -crusting and edema of eye lids
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objective pediculosis pubis
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-lice, nits, feces, bite sites, black specks -rash: lice bite sites -small erythematous papules, peri umbilicated -secondary excoriation and infection
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sites pediculosis pubis
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-pubic hair -occasionally axillary (armpits) and eyelashes -rarely chest and beard
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pedicculosis pubis treatment
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-1st remove all visible lice and nits -body wash -eye lashes: smother with lacrilube or other occlusive ophthalmic ointment, lid hygiene
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treatment pediculosis pubis
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-treat: sex partners, family members, roommates, close contacts -environment: decontaminate bedding and clothing in high temperature
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signs and sx pediculosis capitis
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-may be asymptomatic -brownish fecal matter in hair (esp near ear) -itchiness of neck, scalp, ears -secondary infection of bites -fever and enlargement of cervical lymph nodes
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skin signs and symptoms pediculosis capitis
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pruritus of the back and sides of scalp -bite Rxn -eczema, excoriations, fever -postoccipital lymphadenopathy -secondary infections of bites, S. aureus
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pediculosis capitis treatment
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-first line: OTC permethium (Nix) 1% cream rinse X 10 min. repeat in 7-10 days -second line, pyrethin (RID) for recalcitrant cases -treat family members, roommates, close contacts -decontaminate bedding and clothing
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pediculosis corporis
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body louse -larger: 2-4 mm -life span 18 days -body louse does not live on body -lives and lays eggs in seams of clothing or bedding
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Demodex
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eyelash mites
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epidemiology demodex
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-higher freq in males and older adults
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demodex assoc with which ocular conditions?
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-refractory blepharitis, rosacea, acne vulgarus and dry eye
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signs and symptoms demodex
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-transferred between host (direct contact) to eyebrows, hair and the sebaceous glands on the nose -most infestations have little to no adverse sx -most common symptom is early morning itching and irritation -Most common finding is blepharitis with collarettes
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demodex treatment
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-lid and face hygiene -wash face daily and lid/lashes -tea tree oil
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tea tree oil
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-in office treatmennt -cliradex; 2-step Tx, lash cleaning scrub/pad an a skin cream hs -D/C makeup X one week, replace old -wash bedding/pillow cases weekly warm to hot
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bed bugs
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oval shaped, wingless, light brown to reddish-brown color with bands
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epidemiology bed bugs
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-hematophagous (bloodsucking) -feed on humans only when other prey absent -feed mostly at night, attracted by CO2, warmth -prefer exposed skin: face, neck and arms
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subjective bed bugs
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-large pruritic (itchy) welts -often in line -rxn varies from not visible to prominent nodules and blisters -hands, wrists, face, trunk, most common sites
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treatment bed bugs
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-bite rxn -oral antihistamines, topical hydrocortisone -environmental -elimination of bugs and eggs harborage -pesticides -natural predators
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triatominae
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conenose bugs, "kissing bugs" or assassin bugs
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Chagas Dz cause
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-caused by trypanosma cruzi parasite -kissing bugs feed at night, are attracted to host's CO2 and heat -bite is painless, feeding in ;10 min dropping feces as feeds -often bites on the face, if bite is near lids the eye swells -Chagas transmitted to host through the kissing bugs feces
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Chagas Dz signs and symptomsr
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-fever and fatigue -diarrhea and vomiting, some develop myocarditis -decades later 30-40% develop enlarged heart, arrhythmias, heart failure -some develop enlarged colon and megacolon
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fleas
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-hematophagy external parasites -wingless, 1.5 to 3.3 mm size -agile dark brown -life span: 90 days
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flea bites
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-formation of a slightly raises swollen spot with a single puncture point at the center ;cm -appear in clusters or lines of two -can remain inflamed for up to several weeks
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flea bites tx
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-oral antihistamines, topical hydrocortisone
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trombiculidae/mites
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-chiggers, harvest mites, red bugs, berry bugs, scrub mites
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chiggers
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-preference for ankles and sun exposed areas -attach to skin, pierce, inject enzymes to digest cellular contents -do not "bite", burrow, lay eggs nor suck blood rash: pruritic red, papules, or wheals at "bite" site
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tx chigger bites
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-OTC hydrocortisone benzocaine -OTC calamine lotion, New Skin, after bite
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Ticks
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hematophagy external parasites -hard and soft ticks deer tick, dog tick, lone star
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subjective ticks
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-asymptomatic to pruritic -occasional bruising around bite -tick body protruding from bite
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tick are vectors for?
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-Rock mt spotted fever -lyme Dz -Q fever -Colorado tick fever -African tick bite fever -Crimean congo hemorrhagic fever -tularemia -tick-borne relapsing fever -tick-borne meningoencephalitis -mammalian meat allergy
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rock Mt. spotted fever
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-incubation 3-14 days -fever/chills, malaise, severe HA, nausea/vomiting -within day rash on wrists, 2-4 days becomes hemorrhagic
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Lyme Dz bite
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deer tick -erythema chronicum migrans -occurs 1-2 weeks after bite -rapidly enlarges
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non-poisonous spider bites sx
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-painless -minimal local Rxn -little tissue necrosis -note: most spiders cannot puncture the skin or fangs are too short
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non poisonous spiders that bite
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-garden -wolf
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poisonous spider bites
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-black widow -neural toxin -brown recluse -tissue necrosis toxin
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black widow bites
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-will see two pin point marks -sx acute pain with bite -minimal local rxn
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black widow bite sx
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-followed by local or generalized severe muscle cramps, abdominal pain, weakness and tremor -in severe cases symptoms advance to nausea and vomiting, drop in BP leading to faintness and dizziness -later chest pain and respiratory difficulties may follow
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black widow treatment
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medical treatment is necessary if sx are moderate to severe -equine-derived antivenom
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brown recluse bites
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-usually painless, occasional burning -sx 2-8 hours after bite, redness to pale ring/ hemorrhage or a "bulls-eye" pattern
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sx 12-48 hours after brown recluse bite
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-center or lesion sinks and blisters -hemorrhages in ring pattern -later turns bluish then black as tissue necroses
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treatment brown recluse spider bite
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-ice to reduce pain, elevation of extremity site -topical antibiotic ointment (polymixin/bacitracin) -OTC pain relief and oral antihistamine -tetanus prophylaxis
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puss moth caterpillars
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-if picked up, rubs or is brushed against the skin, the venomous hair become embedded to cause rxn
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puss moth caterpillar rxn sx
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-intense throbbing pain, burning and a rash with erythematous spots
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centipede
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larger species can inflict a painful bite causing redness and swelling -sx last ;48 hours -tx: ice and for rash OTC corticosteroid cream
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house millipedes
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secrete a toxin that if after handling or contact is very irritating, causing an acute ocular reaction if eye is rubbed
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3 basic groups hymenoptera
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ants, bees, wasps
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differential bee/wasps sting
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if sliced or coma shape likely a bee if a straight puncture likely a vespid (wasp/yellow jacket)
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sting/bite of fireant
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pruritic or burning-painful small red raised lesion that is often pus-filled in 6 to 24 hours -the redness and swelling extends well beyond the sting site
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mosquito bore illnesses
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-arboviruses (arthropod-borne virus)/flaviviruses -yellow fever -dengue fever -west nile -Japanese encephalitis -zika parasites -filariasis -malaria
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malaria transmitted by what kind of mosquito?
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anopheles
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sx malaria
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always fever and flu-like sx that come and go -chills, sweats, HA, muscle aches, malaise -vomiting, abdominal pain, diarrhea, cough and jaundice
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prevention malaria
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-chloroquine drug of choice, qweekly, safe -mefloquine -others: atovaquone, doxycycline
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treatment malaria
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-chloroquine + primaquine -chloroquine for sensitive P. falciparum -quinine + doxycycline for resistant P. falciparum
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life cycle encephalitis viruses
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-culiseta mosquito transmit infection among small wild birds of the atlantic and gulf coast states -species of aedes mosquitoes carry infection from wild-bird reservoir to dead-end hosts (horses and humans)
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vector west nile fever
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culex mosquitoes, others
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symptoms west nile fever
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abrupt onset: myalgias, headache, fatigue, arthralgias, rash, splenomegaly
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Japanese encephalitis
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flavivirus -endemic in se asia hosts: old world bird species
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dengue fever
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SE Asia, central Africa, south America classic: Breakbone fever- flu-like illness with severe myalgias, macculopapular rash and leukopenia
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dengue fever sx
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children: mild, ow fever, fatigue, runny nose, cough adults: moderate to severe, high fever, HA, severe body aches in back, legs and joints, swollen lymph nodes,occasional face rash
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dengue hemorrhagic fever
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-sx shock and hemorrhage complicate classic symptoms -over reacting antibodies from previous infection -human reservoir
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zika symptoms
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-conjunctivitis/photophobia -rash -fever -headache, fatigue -myalgias, arthalgias -pruritus
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zika complications
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-uveitis -can result in Guillain-Barre syndrome -can spread to fetus -can spread from men to sexual partners
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prevention zika
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-three D's: drain, dress, defend drain: eliminate standing water dress in light-colored, loose fitting clothing defend by using EPA-approved repellants
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Dermatological bug bite mimickers
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-acne -factitious dermatitis -impetigo -rhus dermatitis -MRSA
