Case 19
Zeb Pike, Leia King, Mary Currier,
Ashley Sherertz, and Manuella De
Carvalho
Symptoms
Garret Danigan - 27 year old man
● Awoke to hand shaped rash on leg
● One week earlier - received mangos and
rested his hand on his leg while peeling
the fruit
● Contact Dermatitis
Symptoms
Contact Dermatitis
● More than 3 million
cases in the U.S.
yearly
● Skin rash caused
by contact with a
certain substance
or irritant
Test and Diagnosis
Identifying what's causing symptoms and
figuring out whether you have the irritant or
allergic type
● A thorough medical history
and physical exam
● A patch test - contact
delayed hypersensitivity
allergy test
Patient History
A previous occurrence of the rash happened
during a summer a few years earlier
● On hands, arms, and legs
● Most likely due to poison ivy
Past Summer Exposure
● Benadryl - not effective
● One week of corticosteroids cleared up
the contact dermatitis
Corticosteroids
Used when the body’s immune system
causes an unwanted response
● Lessen inflammation by limiting the
amount of inflammatory signals that cells
can produce
● Inhibit cell proliferation
Corticosteroids
Can be taken by:
● Mouth - Help treat inflammation associated with
chronic conditions
● Inhaler or intranasal spray - Control
inflammation associated with asthma and nasal
allergies
● Topically - Help heal skin conditions
● Injection - Help treat inflammation of tendinitis
Benadryl
● Antihistamine
o blocks the action of
histamine in the
body
o helps to relieve the
symptoms
● Was ineffective
More Recent Response from Mangos
● The most recent rash
● Exposure to the mango peel
o Caused delayed contact dermatitis
http://www.kitchenfrau.com/wp-content/uploads/2013/11/IMG_0056a-1024x682.jpg
Diagnosis
???????????????
Type IV Hypersensitivity
● “Delayed hypersensitivity reaction”
● First, local immune response to foreign
antigen
o Increase endothelial cell adhesion molecule
expression → leukocyte accumulation at
tissue site
● Antigen engulfed by macrophages and
monocytes
Type IV Hypersensitivity
● Antigen presented to specific T-cell receptor
● Macrophages → secrete interleukin and
lymphokines → form giant cells
● Interleukins mediate communication
● Activation of cytotoxic T-cells is possible
● Key mediators:
o CD 4+ Helper T-cells
o CD8+ T-cells
Type IV Hypersensitivity
What is different about Type IV
hypersensitivity reactions when
comparing to the other types?
Mechanisms
Immune Response
https://www.youtube.com/watch?v=e1X_7jqxEzA - Type IV Hypersensitivity - Delayed Type [HD Animation]
Question 1
Type IV hypersensitivity responses to poison
ivy result in damage to the skin at the point
of contact. What type(s) of cells are
responsible for this damage?
Question 1
Cytotoxic T-cells and macrophages can
respond to affected areas when activated by
an APC
● Cytotoxic T-cells
○ respond to target cells
● Macrophages
○ manufacture large amounts of hydrolytic
enzymes
○ responds in a less specific target approach
Question 2
Why did the patient have the same type of
response to both poison ivy and mango
skin?
Question 2
● Mangos and poison ivy belong to the
same plant family, Anacardiaceae
● Both poison ivy and mango trees create
urushiols
o Urushiols cause irritation upon contact
Urushiols
● Organic allergen
● Mango flesh - very low levels of
urushiol
● Most sensitive people can eat
the fruit without problem as long
as someone else peels it
http://www.cyberlipid.org/images/pict208.jpg
Urushiols
http://waynesword.palomar.edu/ww0802.htm
Question 3
How is a Type IV hypersensitivity different
from an allergy (Type I hypersensitivity)?
Question 3
Type 1 (immediate) - response caused by the IgE
mediated response of histamine released by mast
cells and basophils
Type 4 (delayed) - T- cell mediated response and
occurs by CD4+ cells and Th1 cells releasing
cytokines to attract CD8+ cytotoxic T-cells to
destroy marked cells.
Question 4
Why were corticosteroids effective as
treatment in the case while Benadryl was
not?
Question 4
Benadryl is an antihistamine
● Does not affect the rash due no histamine
being produced
● Type 4 hypersensitivity does not trigger
mast cells or basophils
● Treatment for that kind of immune
response does not work
References
● http://www.mayoclinic.org/diseases-conditions/contactdermatitis/basics/definition/con-20032048
● http://my.clevelandclinic.org/health/drugs_devices_supp
lements/hic_Corticosteroids
● http://www.bio.umass.edu/micro/immunology/poisoniv.h
tm
● http://en.wikipedia.org/wiki/Anacardiaceae
● http://www.nutritionatc.hawaii.edu/HO/2005/309.htm
● http://www.mayoclinic.org/diseases-conditions/contactdermatitis/basics/tests-diagnosis/con-20032048
References
http://www.benadryl.ca/remember-the-dryl/how-to-treatallergic-reactions
http://www.aascare.com/our-services/patch-testing/
https://docs.google.com/presentation/d/1QDV_bQ0EAOdzgGlYd7Sn26wdGxXXTALBoGitp8nTz8/edit#slid
e=id.gae9c55747_0_0
http://www.ncbi.nlm.nih.gov/books/NBK10756/