Bugs, Bugs, and Bugs! Infestations and Bites E.J. Mayeaux, Jr., M.D. Professor of Family Medicine Professor of Obstetrics and Gynecology Louisiana State University Health Science Center Shreveport, LA
Scabies • Most common human mite infestation • Caused by Sarcoptes scabiei which survives solely in human skin
LSUHSC-S Family Medicine Courtesy of the Color Atlas of Family Medicine
Scabies • Tiny reddish papules and severe itching • Spread person to person via direct contact, clothing, bedding, and shared objects • Female mite tunnels under skin in stratum corneum and deposits eggs and fecal pellets LSUHSC-S Medicine Courtesy of theFamily CDC/Susan Lindsley
Scabies • Larvae hatch in a few days, mature in 2 weeks and live 30 days • Humoral immune sensitivity • Hypersensitivity to mite results in pruritis LSUHSC-S Medicine Courtesy of the Color Atlas ofFamily Family Medicine
Scabies • Norwegian scabies is a severe form in immunocompromised patients • Sx: Intense pruritis, worse at night or after hot shower
LSUHSC-S Family Medicine Courtesy of the Color Atlas of Family Medicine
Scabies • Pink linear burrows up to 1-2 cm, with pinpoint erythematous vesicles and papules Courtesy of Richard Usatine, M.D.
Mite
Burrows with dermoscopy LSUHSC-S Family Medicine
Scabies Diagnosis • Clinical presentation – Itching and typical rash • Symmetric, papulovesicular lesions accompanied by macules, pustules, scaly plaques • Interdigital webs, wrists, axilla, buttock and groin
– Can do skin scraping for mite – Poor NPV – Liquid tetracycline followed by alcohol • Burrows fluorescence yellow gray with Wood’s Lamp
– Ink test LSUHSC-S Family Medicine Courtesy of the CDC
Scabies Treatment N.Z. • Permethrin 5% (Elimite, Acticin crm) – Apply head down, leave 8-14 hrs, wash • Repeat in 2 weeks • Pregnancy Category B (Safer) • >2 months, Better for children
• 0.5% Aqueous malathion lotion – Apply from chin to toes and left on for 24 hours
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Scabies Treatment • Less effective: topical benzyl benzoate, synergized natural pyrethrins x 3 days • Infants: Monosulfiram - at dx, 1 day & 1 wk • Diphenhydramine, hydroxyzine, and midpotency steroid creams for symptoms • Wash clothes/linens in HOT water and remove from body contact for >72 hours – May be dry cleaned or stored in bags >20° C or 25 years – Lacks FDA indication – 400 to 800 mg/d for 3 to 5 days – Cure rates >92%
• Cryotherapy is harmful LSUHSC-S Family Medicine
Hymenoptera • Have poison glands • Stings produce immediate pain • Prevalent worldwide
• European Wasp • Courtesy of Wikipedia Commons and Fir0002/Flagstaffotos
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Hymenoptera • Reactions to hymenoptera stings: – Local erythematous wheal that subsides within a few hours (normal reaction) – Extensive swelling and induration that lasts for days due to venom-specific IgE and cell mediated reaction – Bullous reactions – Systemic anaphylaxis including urticaria, angioedema, bronchospasm and hypotension LSUHSC-S Family Medicine
Hymenoptera Treatment • Quickly remove stinger (by scraping?) • Cool compresses, calamine lotion, analgesics and antihistamines • Steroids for severe swelling
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Hymenoptera Treatment • Scraped off vs pinched? • Response to honey-bee stings was assayed measuring size of resulting weal • Findings: Weal size increased as time from stinging increased, not removal method • Quick removal, without concern for the method of removal best • Visscher K, Vetter RS. Removing bee stings. Lancet 1996; 348: 301–02P.
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Hymenoptera Treatment • Anaphylaxis should be managed by: – Subcutaneous adrenaline 0.5 ml 1:1000 – Oral, IV or IM antihistamines – Oxygen – Systemic steroids if symptoms persist for longer than 20 minutes – Venom immunotherapy – EpiPen
LSUHSC-S Family Medicine
LSUHSC-S Family Medicine
