Question | Answer |
hallmark lesion of arthropod bite | Papular urticaria |
Papular urticaria: increased risk of | secondary infxn |
Papular urticaria usually due to: | flea, mosquito, bedbug |
How often do black widow bites cause serious reactions? | 25% |
R-I-C-E for spider bites: | minimizes inflammation & slows enzyme activity |
Scorpion sx | immediate sting, followed by paresthesia |
Scorpion effects | systemic > local (neurotoxin) |
Where on body is scabies seen? | Mites prefer areas where skin is thin. If <1 yo: head/scalp/neck |
AKA crusted scabies (severe) | Norwegian scabies (seen in immunocompromised patients) |
Scabies diagnosis is usually: | clinical (but also with mineral oil) |
Uses stylostome for feeding | Chiggers |
Chiggers: lesions | papules or hives (ankles, backs of knees, groin, axillae) |
Tx chiggers | hot soapy water, antihistamine, topical steroid |
Possible role in rosacea: | demodex mite |
Tick bite: rxn | local, erythema; then induration, nodular; rare tick granuloma (Lyme: erythema migrans = bullseye) |
Lyme dz: cutaneous lesions | lymphocytoma cutis (European); acrodermatitis chronica atrophicans; both bluish |
Chevron shaped bite | centipede |
Millipede bite: | they don’t bite; secrete oily substance, may burn or blister |
This may be only sx of body lice | pruritus |
Head lice: pts often have: | cervical adenopathy; scalp pruritus, excoriations |
Head lice tx | 1% permethrin; retreat in 1 wk |
Pubic lice tx | 5% permethrin or lindane |
These cause more dz than any other arthropod | flies |
Bedbug lesion: classic: | papular urticaria but may be vesicular, eczematous |
Bedbug bites: arrangement | linear arrangement in clusters (painless bites) |
Erucism = | caterpillar dermatitis |
Lepidopterism: | systemic illness with urticaria and airway hypersensitivity |
Moth / Butterfly exposure Tx: | oral antihistamines, topical ointments w/menthol or camphor, topical c’steroids, oral steroids for severe cases; Remove setae with adhesives |
Flea bites: lesions: | erythematous macules and urticarial-like papules; Excoriations and secondary infection common |
Fleas: Tx for sx | topical steroids, oral prednisone for severe urticarial reactions (triamcimolone), antibiotics for secondary infections; advise lesions will be around for a while |
Bee/wasp sting reactions | large reactions can develop ~ 6-24 hrs after sting and peak at 48hrs |
Diff btw delayed hypersensitivity rxns from stings & cellulitis | both are warm; sting: area of induration, not tender; poss slightly pruritic |
Fire ant rxn | immediate pain followed by wheal & flare reaction (1 hr); sensitized pts may develop striking bullous reaction in an unusual ring shape |
Fire ant tx | local cleansing, ice, oral antihistamine. Oral steroids for severe cases. Update tetanus if needed |
Lesion appearance of brown recluse bite | pale gray sinking macule, slightly eroded in center; halo of tender inflammation/hemo |
Scabies tx in pediatric patients | NO LINDANE (KWELL). Permethrin (Elimite) is drug of choice |
Scabies adult tx | Permethrin ($ > lindane). lindane (some regional resistance). Alt: crotamiton 10% cream; sulfur cream; benzoyl benzoate |
Bite w/ fever, lacrimation, rhinorrhea, bradycardia, HTN, tachyarrhythmias = | Black widow (neurotoxin) |
Bite with local edema, erythema, central necrosis | Brown recluse |
Intense pruritis especially at night. Burrow-like lesions at wrists, elbows, hands, webs of fingers. Due to: | Scabies |
Black widow bite mgmt | Lactrodectus antivenin IM. Supportive airway & circulation. Benzos prn mx spasm; pain control. |