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

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 - 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

Urushiols

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 ● dermatitis/basics/definition/con http:// dermatitis/basics/definition/con ● lements/hic_Corticosteroidshttp://my.clevelandclinic.org/health/drugs_devices_supp lements/hic_Corticosteroids ● tmhttp:// tm ● ● ● dermatitis/basics/tests-diagnosis/con http:// dermatitis/basics/tests-diagnosis/con

References allergic-reactions bQ0EAOdzgGlYd7Sn26wdGxXXTALBoGitp8nTz8/edit#slid e=id.gae9c55747_0_0