Wilderness Bites, Wilderness Bites, Stings, Rashes and Stings, Rashes and Allergic ReactionsAllergic Reactions

A 45 year old male presents with lip swelling after drinking

out of a soda can with a bee crawling on it

What type of What type of hypersensitivity hypersensitivity reaction is this?reaction is this?

How should this be treated?

Immunology: Type I Reaction

Hymenoptera Multiple Antigens 40-50 Deaths/yr US Rare deaths from stings alone (> 50 stings) Africanized Bees

Types of hypersensitivity reactions

Type I : IGE mediated/ anaphylactic ..immediate …allergic rhinitis

Anaphylaxis

IGE mediated 90 % urticaria or angioedema The more rapid the reaction the more severe May be delayed ( up to 48 hours) More severe reactions in older individuals Look for:

– Dizziness– Wheezing– Vomiting

Treatment

Prevent further stings Calm the patient and friends Rest Elevation Ice

Vive la Difference

Bees sting once but have a muscular stinging sac

Wasps can sting multiple times

Treatment

Antihistamine– Benadryl: po v. IM

• 50 mg or 1 mg/kg– H2 Blocker if severe

• Cimetidine

– 300 mg po or IM Epinephrine

– Epi –pen (jr)

• 0.3mg adult…0.15 mg child

• $65

Treatment

Prednisone– Reduces late phase reaction– 1-2 mg/kg

Glucagon– Refractory symptoms on a B-blocker– 1-5 mg IM

Albuterol inhaler for wheezing Fluids/ pressor support

What would make you What would make you want to evacuate the want to evacuate the

patient?patient?

WHEN TO EVACUATE:

Systemic symptoms

Diffuse Urticaria

History of severe reactions

On B-Blocker

Refractory to Benadryl

How long should you monitor the patient?

~ 6 hours 50 % severe in 10 minutes Most deaths < 1 hour Rare worsening after 5 hours

How long to treat?

3-4 days with anti-histamines and steroids

How likely is the patient to have the

same reaction if stung again?

Good Question!

In adults: – Variable studies: ~ 10 to 60 % who had

Anaphylaxis may have no or mild reaction to subsequent sting: 10- 20 % worse reaction

In Children:– Rare severe reaction < 10 y.o.– ~ 10-20 % with severe reaction will have

similar subsequent reaction.

What should the patient carry with him in case

this happens again?

What to Carry?

Benadryl capsules Epi-pen

What would make the patient consider immunotherapy in the future?

Occupation Desire for wilderness experience Severity of Reaction

95 % effective 3- 5 years of therapy Hornets, honeybees, fire ants

2 weeks later the patient returns 2 weeks later the patient returns to the ED withto the ED with

Malaise, Joint pain, occasional Malaise, Joint pain, occasional itching.itching.

Type III: Immune Complex Formation

Serum Sickness– 7-14 days– Malaise, arthralgias, proteinuria

Arthus Reaction:– Site of the sting– 8-12 hours– Blister formation

Resolve in 7-14 days– Antihistamines, Steroids if severe

A 26 year old gardener was cleaning brush near her cottage. She presents with a pruritic rash on her neck. What is your diagnosis?

Cutaneous Lepidopterism

Caused by the larvae of the Brown-tailed moth

Treatment– Tape removal of setae– Topical steroids, – Benadryl– Systemic steroids

May induce asthma

Lyme Disease Clinical Pearls

The erythema chronicum migrans (ECM) rash appears in 2-12 days after the bite…i.e engorgement.– It is caused by the spread of Borellia – A rash that occurs within the first day of a tick bite is

not ECM.– ~ 70 % of infected patients will get ECM– ECM may mimic cellulitis.– Multiple ECM sites : immunocompromised or

systemic disease.

Lyme Disease Prophylaxis

Doxycycline 200 mg po once– Decr. Infection rate from 3.5 % to 0.4%

Indications:– >=12 years old ( doxy ok >=8y)– Engorged deer tick ( if flat no doxy)– Can’t talk the patient* out of it.

• (* mother, grandmother…etc)

<8 yo…????

Lyme Disease Treatment

ECM, Bell’s, 1st degree block:– Doxycycline 100 mg b.i.d. : 14-21 days– Amoxicillin 15 mg/kg t.i.d.: 14-21 days

Serious Cardiac or Neuro– Ceftriaxone 75 mg/kg daily: 14-21 days

Arthritis: – As per ECM but for 28 days

Lyme Disease Cousins

Anaplasmosis:– Causes low platelets and leukopenia

Babesiosis: – Causes anemia and hemolysis

A 40 year old man presents with an erythematous macular papular rash on his bilateral lower extremities. He was swimming today in Little Sebago Lake and became very itchy within an hour of getting out of the water.

Escagot’s Revenge or Swimmers Itch

Cercarial Dermatitis May be caused by the parasite Trichobilharzia

regenti Complicated life cycle involving both a bird

and a mollusc When exposed to humans, borrows into skin

and causes irritation Most cases do not require medical attention

A 22 year old “sternman” presents with a painful, swollen left hand. He states he has “redfish poisoning”. It is wicked bad this time. What is his medical diagnosis?

Erysipeloid

Well circumscribed erythema Fishing, shellfish, poultry industry Not systemically ill Sensitive to penicillins, cephalosporins,

fluoroquinolones Resistant to vancomycin Erysipelothrix rhusiopathiae

– Gram positive rod

A 5 year old is exploring a tide pool and has sudden pain in his right foot. Mom sees a dark dot on the sole of the foot. The dot is the spine of the Green Sea Urchin (Strongylocentrotus droebachiensis)

What should be the treatment?

Wounds in a Marine Environment

Local wound care …removal foreign bodies– Vinegar soaks or hot (105F) water for urchin

spines Immunocompetent: no prophylaxis for

minor wounds Immunocompromised, Liver disease, :

Cipro …2nd line: Bactrim

A 28 year old paddle boarder wearing a thin wetsuit went swimming earlier today in the river. He presents to the ED tonight with a painful itchy rash. What is his diagnosis?

Sea Bather’s Eruption

Larva of Jelly fish or anemone Urticaria or papular within an hour of exposure Under swim suit or nape of neck Wash with salt water…scrape off cysts Antipruritic treatment Sun screen may be preventative

It is early september and a 65 yo man with no psych history presents with agitation and confusion for the past 2 days. He has a low grade temp and complains of nausea and a headache. What is your differential?

CSF:

20 WBC, 90 % lymphsGlucose: 70 mg%Protein: 60 mg%Gram stain: negative

West Nile Virus:

Flavivirus– Japanese Encephalitis

80 % asymptomatic 19 % febrile illness 1 % neuroinvasive

Intermediary hosts: Crows/robins

Eastern Equine Encephalitis

1 human case in Maine

Prevention

Barrier– Head nets– Light colored clothing– Socks over pant legs

Behavior– No scents– no baths– Avoid vigorous activity– Avoid dusk and dawn

Insect Repellents

The Pretenders– Thiamine– Skin So Soft, bug guard– Citronella– Oil of Eucalyptus– Soy Bean oil ( “Blocker”)

Insect Repellents

DEET is the word– Safe even for kids– Long lasting ( Ultrathon )– Effective against a variety of insects– 30% enough

• Dissolves plastics

• Seizures

Insecticides

Permethrin– Very effective combined with DEET

Allethrin– Thermacell

Attractants

The mosquito magnet– “converts propane into carbon dioxide

(propane tank not included), heat, and moisture to simulate human breath”