5
- if an ulcer develops: cleanse several times each day (hydrogen peroxide or povidone-iodine
solution)
-
treat
pruritus
with
antihistamines
-
prophylactic
antibiotics
(cephalosporin
or
erythromycin) may be beneficial, but are controversial
- caution patients/family: nothing proven to decrease extent of dermonecrosis
-
controversial
modalities:
- Steroids (either intra-lesional or systemic): no proven benefit
- Dapsone and Colchicine: unproven
- as polymorphonuclear leukocyte inhibitors, may limit PMN participation in the propagation
of the local lesion
-
with
dapsone
there
are
significant
potential complications (dose-dependent hemolytic
anemia
and
methemoglobinemia)
- should never be used in children
- side effects of colchicine are less worrisome, but it has yet to be formally studied in brown
spider bites
- Excision of the site:
-
definitely
not
indicated
(impossible
to predict extent & severity of lesion early)
-
any
required
surgical
procedure
should
be postponed for at least 6-8 wk (to ensure the
necrotic
process
has
been
completed)
- Hyperbaric oxygen therapy may be useful in severe wounds
- Antivenin: an experimental product has been produced
- appears to decrease the extent of dermonecrosis, but not commercially available
- would only be useful if an accurate lab test is developed to identify brown spider bites early
ii.
Systemic poisoning:
- ensure adequate hydration, maintain electrolyte balance, administer antipyretics (avoid
salicylates)
and
analgesics
-
systemic
steroids
may
be
beneficial in patients with hemolysis (has yet to be studied); oral
prednisone
1
mg/kg/d
for
2-4
d
- blood products as indicated for anemia or thrombocytopenia
- heparin may be beneficial for DIC
- if hemoglobinuria occurs: alkalinize urine & maintain adequate hydration
- if renal failure occurs, dialysis may be indicated
c.
Disposition/Outcome:
- admit patients with rapidly expanding lesions or evidence of systemic poisoning
- discharged patients should have daily wound & lab checks for the first few days
- there have been no reports of deaths in patients bitten by positively identified brown spiders in the
U.S., but there is significant risk of death from systemic loxoscelism (especially in children)
C.
Other Spiders:
- the following U.S. spiders are relatively harmless, but may produce painful bites and a small amount
of local necrosis:
-
Tarantulas
(family
Theraphosidae)
-
Wolf
Spiders
(Lycosa sp.)
- Jumping Spiders (Phiddipus sp.)
- Orb Weavers (Argiope sp.)
- Hobo Spider (Tegenaria agrestis) - potential for systemic toxicity (at least one death reported)
- treat the bites with local ice, analgesics, tetanus prophylaxis prn, conservative wound care
V. Scorpions:
A.
Introduction:
- >1,400 species in the world
