Case 19Zeb 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

● Antihistamineo 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

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Type IV Hypersensitivity

● “Delayed hypersensitivity reaction”● First, local immune response to foreign

antigeno 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-cellso 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/contact-dermatitis/basics/definition/con-20032048

● http://my.clevelandclinic.org/health/drugs_devices_supplements/hic_Corticosteroids

● http://www.bio.umass.edu/micro/immunology/poisoniv.htm

● http://en.wikipedia.org/wiki/Anacardiaceae● http://www.nutritionatc.hawaii.edu/HO/2005/309.htm● http://www.mayoclinic.org/diseases-conditions/contact-d

ermatitis/basics/tests-diagnosis/con-20032048

References

http://www.benadryl.ca/remember-the-dryl/how-to-treat-allergic-reactionshttp://www.aascare.com/our-services/patch-testing/https://docs.google.com/presentation/d/1QDV_-bQ0EAOdzgGlYd7Sn26wdGxXXTALBoGitp8nTz8/edit#slide=id.gae9c55747_0_0http://www.ncbi.nlm.nih.gov/books/NBK10756/