Parasitic Parasitic Infestations, Infestations, Stings & Bites Stings & Bites Part 2 - Another Part 2 - Another Spine-Tingling Spine-Tingling Lecture from…Lecture from…KCOM/TX Dermatology

Residency ConsortiumDan Ladd DO

Loaiasis

Aka Loa Loa, Calabar Swelling, Fugitive Swelling, Tropical Swelling

Asymptomatic localized subQ swellings, size of a hen’s egg

Prediliction for loose tissues such as eyes, frenulum of tongue, genitalia

Mango fly Chrysops dimidia or silacea

Tx: Diethylcarbamazine

Loaiasis

Onchocerciasis

River BlindnessCentral & South America, MexicoPretibial depigmentation: leopard skinThickened skin: elephant skinMay develop into subQ nodulesMazzoti test + if edema, pruritis, fever & arthralgias w/ 50mg diethylcarbamazineTx: Ivermectin 150mg single dose

Black fly Simulum

Leopard skin, Elephant skin

Trichinosis

Inadequately cooked pork, bear or walrus meatPuffy eyelid edema, red conjunctiva and sometimes urticaria, fever, HA, muscle pains, neurologic S&S.20% have maculopapular rash, very itchy, responsive to corticosteroids.Diagnosis by muscle biopsyTx: Albendazole 400mg bid for 2w.

Trichinella spiralis – muscle bx

Phylum Arthropoda

MyriapodaCentipede

Millipedes

InsectaCaterpillar

Moth

Arachnidia

Myriapoda – Centipede StingsPaired hemorrhagic puncta with erythematous swelling progressing to brawny edema or lymphangitis and lymphadenopathy.

Scolopendra species, 15-20cm

Tx: Rub with garlic, local anesthetic injection.

Scolopendra sp.

Myriapoda – Millipede burns

Millipede bodies secrete a toxic liquid that causes brown discoloration, progresses to erythema & vesiculation – intense stinging and burning pain

Tx: wash site immediately, topical steroids.

Lepidoptera – Caterpillar Dermatitis

Nettling hairs contain toxin producing local pruritic erythematous macules and wheals.

MC campers, children playing in trees and lumberjacks in Fall.

Nygmia phoerrhoea (brown-tail moth)Megalopyge opercularis (puss)Sibine stimulae (saddleback)Megalopyge crispata (crinkled flannel)Tx: Antihistamines, resolves 48 hours.

Brown tail moth

Saddleback

Lepidoptera – Moth Dermatitis

Hairs of the moth – urticating toxinEuproctis chrysorrhoea (brown tail)Cossus cossus (goat)Dicranura vinula (puss)Lymantria dispar (gypsy)Hemenocampa pseudotsugata (Douglas fir tussock)Tx: oral steroids help, lasts 1 week

BROWN TAIL MOTH

GYPSY MOTH

GOAT MOTH

DOUGLAS FIR TUSSOCK

Hemiptera – Bedbug BitesAka Cimicosis, Cimex lectularis

Smelly parasite with non-functioning wings. Hides in crevices by day and feeds on human blood at night.

“Breakfast-Lunch-Dinner” linear bites

Sensitivity at site due to saliva

Hepatitis B surface antigen has been repeatedly demonstrated in the bugs, but transmission is controversial

Tx: Pt: topicals, House: call exterminator.

Hemiptera – Reduviid Bug Bites

Aka Kissing Bug, Assasin bug, conenoses

Attack face when asleep, bite is painless, bug defecates and rubs feces into wound, spreading Trypanosoma cruzi

Chagas Disease

Anoplura

Pediculosis (Phthiriasis)

Pediculosis Capitis

Pediculosis Corporis

Pediculosis Pubis (Crabs)

Pediculosis (Phthiriasis)

Pediculus humanus (head & body)

Phthirus pubis (pubic or crab louse)

Attach and suck blood, saliva is antigenic and creates dermatitis

Lice may transmit endemic typhus, relapsing fever or trench fever.

Pediculosis Capitis

MC in children, scalp usually pruriticDiagnosis straightforward.Peripilar hair casts easily differentiated b/c moveable, but trichorrhexis nodosum mimics nitsTx: Apply Permethrin 1% Cream Rinse (Nix) to DRY hair, then rinse out after 30-60 minutes. Do not shampoo for 24 hours afterwards.

Pediculosis Capitis

Pediculosis Corporis

Aka: Pediculosis Vestimenti or Vagabond’s Dz. Likes pressure areas beneath collar, belt or in bedding.LICE RARELY FOUND ON SKIN.Dx: Generalized itching, parallel scratch marks, hyperpigmentation, LSC & red maculesTx: Laundering clothing and bedding, 1% Malathion powder, 10% DDT may be dusted onto inner surface of underwearBest to discard clothing altogether as lice may live in clothing for 1 month without a blood meal

Pediculosis Pubis (Crabs)

MC Adults, STD, MC genitalia but may invade hypogastrium, axilla or eyelashes.

LICE COMMONLY FOUND ON SKIN

Pthirus pubis

Maculae ceruleae, bluish or slate colored papules, blancheable on sides of trunk or inner thighs.

Tx: Permethrin x 10 minutes, Repeat in 1 week, Tx Partner as well. Petrolatum for eyelash lice.

Order Diptera – Dz Associations

Muscidae – tsetse fly, (trypanosomiasis), (myiasis)

Simulidae – black fly (onchocerciasis)

Psychodidae ,Phlebotomus, sandfly, (leishmaniasis, verruga peruana)

Culicidae (mosquitoes), filariasis, malaria, dengue, yellow fever, WNV.

Diptera – 3 main problems

Mosquito bites

Ked itch

Myiasis

Mosquito bites – CulicinaeMoisture, warmth, carbon dioxide, estrogens and lactic acid in sweat attract the mosquito

Pruritic wheal, urticarial reactions.

West Nile Virus vector, mosquitoes acquire it from feeding on infected birds.

Avoid standing water, wear long sleeves.

TX: topical steroids, DEET.

Also vectors for filariasis, malaria, dengue, yellow fever.

Ked itch

Sheep ked = Melophagus ovinus

Yet another bloodsucker.

Woolsorters and sheepherder’s

Pruritic often hemorrhagic papules, nearly always with a central punctum

Deer keds attack people in a similar way, MC hips and abdomen, last 12m

MyiasisInvasion of tissues by fly larvae, eggs hatch, burrow into skin. Wounds MC.

Furuncle with maggots in the center.

Cochliomyia hominivorax (Screw worm) MC cause wound myiasis in USA

Phormia regina (Black Blowfly, USA)

Dermatobia hominis (botfly, New World)

Cordylobia anthropophaga (Tumbu Fly, Africa)

TX: EXCISION OR OCCLUSION W/ PETROLATUM

Blister Beetle DermatitisMeloidae, Oedemeridae release the vesicating agent cantharidinStaphylinidae releases pederinNot biters, vesicant rubs off if beetles brushed against, pressed or crushed on the skinLinear array of vesicle(s), bulla(e)“Spanish Fly” or Lytta vesicatoria best known for medicinal purposesTX: I&D, Cold compresses, Top CS.

Spanish Fly – Rick Lin’s special formula extracted during mating

Carpet Beetle Dermatitis

Anthrenus scrophulariae

Papulovesicular and urticarial involves chest, neck and forearms.

Reddish brown, fusiform 6mm long and covered by hairs

TX: Fumigate house with sulfuryl fluoride

Carpet beetle – note hairs Anthrenus scrophulariae

Bees and WaspsBees or APIDS – venom contains histamine, mellitin, hyaluronidase, HMW acid phosphatase, phospholipase A

Wasps or VESPIDS – venom contains phospholipase, hyaluronidase and a protein known as ANTIGEN 5.

Honeybee stinger stays in the skin and has a sac you must scrape off, because if you pick it up by the sac, you express more venom into the tissues.

Bee and Wasp StingsSymptoms vary from a small pruritic wheal to anaphylactic shock.Bee sting anaphylaxis may be first symptom of mastocytosis.Treatment with IL steroids and xylocaine is highly effective.ASA or meat tenderizer compresses.Anaphylaxis 0.3cc epi 1:1,000 SQSusceptible persons should carry an

Ana-Kit with syringe, epinephrine and Antihistamines

Yellow jacket – MCC of allergic reaction to insect stings

Nest in the ground or in walls, interrupted by outdoor activity

Ants – Fireants most painful

Solenopsis saevissima, invicta, geminata, xyloniS. saevissima is ferocious and vicious: multiple bites in seconds.Intense pain, whealing and eventually sterile pustule with erythematous base, very characteristic lesion.Seizures and mononeuropathy have been reported.Tx: IL steroids oral steroids, SQ epi

“Hasta la vista, baby”. -- Arnold Schwartzenegger, Terminator

Solenopsis saevissima

Pulicosis (Flea Bites)

Human – Pulex iritans

Cat – Ctenocephalides felis

Dog – Ctenocephalides canis

Extraordinary jumpers, no wings

Legs and waist MC sites

Hemorrhagic puncta surrounded by urticarial patch. “zigzag lines” or grouped

Well’s syndrome may occur (eosinophilic cellulitis

Pulex iritans (Human flea) below….

Ctenocephalides felis

Cat flea on the right

Fleas as Vectors of Disease

Xenopsylla cheopis and X. brazilensis are vectors of plague and endemic typhus

Squirrel flea, Diamanus montanus transmits plague and tularemia

Flea Control

Malathion, Chlordane in kerosene, Lindane dusts or sprays, again, may be easiest to call the Orkin man.

Insect repellants OFF!, other DEET and pyrethrum preparations.

Tungiasis

Tunga penetrans

Aka nigua, chigoe, sand flea, jigger.

Reddish brown flea 1mm long

Africa, Central & S. America, India, Pakistan

Pregnant females burrow into skin of ankles, soles, feet and toes.

Lesions become infected and painful

Tunga penetrans

TX: Sx, Abx, Thiabendazole

Aaahhh-nold

Tick Bites & Disease AssociationsDermacentor andersoni – wood tick (USA) & Amblyomma americanum – Lone Star tick (Texas) both transmit Rocky Mountain Spotted Fever, Tularemia & tickborne encephalitis

Ixodes transmit Lyme dz in USA

Dermacentor variabilis (dog) Tularemia

Rhipephalus sanguineus (dog) Rickettsia conorii (Boutonneuse fever)

Ticks also transmit Q fever, Babesiosis, Ehrlichosis, Arbovirus, Viral encephalitis, Hemorrhagic fevers.

Tick Bite Presentations1) Urticarial wheal

2) Tick Bite Pyrexia – 7-12 days of fever, chills, headache, abdom. pain & N/V.

3) “Tick Paralysis” – usually in children, 6 days after attachment, rare, MC head/neck.

Flaccid paralysis of legs, then arms, neck, diaphragm, resembles Guillen-Barre syndrome. Tick toxins block NMJ’s.

Tick removal causes rapid recovery, but death may ensue if tick is not removed.

Other Tick Bite Diagnosis

Ornithodorus tholozani may be a vector for Borrelia duttonii, African endemic relapsing fever

Bite produces typical small inflammatory nodule surrounded by a zone of normal skin with a circumferential brownish ring.

ScabiesDistribution:Circle of HebraImaginary circle intersecting sites of prediliction – areolae, axillae, elbow flexures, wrists, finger webs, umbilicus, lower abdomen, genitalia

Scabies

Papular and burrow-type lesionsFace and scalp spared in adults, but not in infants or immunosuppressed.Burrows may be barely visibleDull red nodules persist in groin, called nodular scabies, may persist after cure, histo = pseudolymphomaNorwegian – heavy crusting, scaling most common in malnourished, immuno-suppressed or pts with neurologic dz.

Sarcoptes scabiei

Scybala

Mineral oil or Acry-Mount on a glass slide with cover slip on top

Scabies Treatment

Norwegian: Ivermectin 200mg/kg weekly x 3.Permethrin 5% cream from head to toe at night, rinse off in AM x 3. May repeat weekly.Lindane rarely neurotoxic to infants Infants and Pregnant women 6-10% precipitated sulfur in petrolatum applied nightly x 3 nightsTreat family members

Animal Scabies

Milder course than human scabies

Dogs, cats, poultry, birds, camels or horses

Self limited, no burrows or mites found.

Cheyletiella Dermtitis

Non burrowing mites that are parasitic on dogs, cats, rabbits

May bite humans leaving itchy dermatitis resembling scabies

Mites easily seen on pets.

Treatment of pet by veterinarian is the only necessary treatment

Demodex mites - DemodicidosisMC adults > 30 yo inhabit sebaceous glands of the nose, ala, forehead, chin and scalp

Significant only if in large numbers.

Readily found in adults without disease – pathogenicity controversial

Occasionally, recalcitrant rosacea patients may benefit from permethrin

Papulonodular AIDS eruptions

Demodex folliculorum – found in contents expressed from seb gland

Chigger Bite

Eutrombicula alfreddugesiMC legs and belt line and other sites where clothing causes constrictionGrass and bushes typically infested in summer or fall aka Mower’s mitesPruritic hemorrhagic puncta surrounded by red swellingsTX: TS, Prophylaxis: (DMP) demethylphthalate solution

Gamasoidosis

Persons who handle canaries, pigeons and poultry

MC arms & hands, papular, urticarial

Diagnosis of urticaria is usually made

Ornithonyssus and Dermanyssus mites infest feathers, bite humans

Take about 1 week longer to resolve than most bug bites, Tx: malathion

Grocer’s Itch

Pruritic dermatitis of forearms

Carpoglyphus passularum – dates, prunes, figs.

Acarus siro and Tyrophagus longior – handling cheese

Grain Itch

Pyemotes triticiLives in grain, attacks harvesters of wheat, hay, barley, oats and other cereals or other farmhands who work around straw.Urticaria papule with vesicle hemorrhagic punctumTX: malathionMite may not be demonstrable in skin.

Scorpion StingHide during daytime in closets, shoes, folded blankets, children’s sandboxes.Any sting by a large scorpion should be considered dangerous because venom is hemolytic and neurotoxicMC USA is Centruroides sculpturatusNumbness, laryngeal edema, profuse sweating & salivation, cyanosis, nausea and paresthesia of the tongueTx: tourniquet, antivenin, phentolamine, atropine, barbituates

MC USA: Centruroides sculpturatus

Latrodectism – Black WidowDark dry places under rocks, in cellars, in wood piles.Severe pain in minutes, spreads from bite site to extremities and trunk, severe GI distress, abdominal rigidity delirium, paralysis. S/S last 2 days.Abdominal pain so severe it may be mistaken for appendicitis, colic or food poisoning. Children may die.Opiods, benzodiazepines, antivenin.

Lactrodectus mactans13mm long, coal black with an orange red hourglass on abdomen

Loxoscelism – Brown Recluse2 types of reactionsLocalized – Necrotic Cutaneous - extensive gangrene, severe edematous painful reaction within the first 8 hours. Starts as bulla with surrounding erythema and ischemia. In one week central dark gangrenous portion may become many cm wide and lasting months before healing.Diffuse – Viscerocutaneous - rare

Loxoscelism Therapy

1) Rest, Ice, Compression, Elevation

2) No hot packs or surgery

3) Dapsone 100mg BID

4) Aspirin

5) Surgery, if any should be delayed 4 to 6 weeks.

6) No benefit to surgical excision, actually increases complications.

Sting Ray Injury

Unwitting victim steps on partially buried stingrayPuncture wound that ulcerates.Immediate sharp shooting pain with edema and cyanosis, symptoms of shock may occurTX: Venom is detoxified by heat, so soak affected foot in hot water x 1 hr.Demerol for pain.

Snake BiteRattlesnake, Cottonmouth, CopperheadVenom = hydrolases, 30 enzymes, anticoagulant, hemolytic, increased capillary permeabilityIf treatment center cannot be reached within 1 hour, tourniquet, incision and suction in first 15 to 30 minutes, antivenin, antibiotics, tetanus toxoid, possibly surgical intervention

UR: MocassinLR: CopperheadLL: Rattlesnake

Lizard Bite

Heloderma suspectum AZ, NM

Paralysis, Dyspnea, Convulsions

Death is rare, Tx= snakebite tx

The End….a special thanks to my enthusiastic and attentive audience