History of Present Illness:

A man in his mid 30’s presents to the hospital with 3 days of worsening forearm pain, itching and redness and 1 days of a red line going up his arm.  He denies any fever or chills.

Vitals & Physical Exam:

Vitals are normal as is the exam other than as pictured below

QUESTIONS:

What is the most likely diagnosis?

  • A) Cellulitis
  • B) Lymphangitis
  • C) Type 4 hypersensitivity reaction
  • D) Tuberculosis

 

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ANSWER: What is the most likely diagnosis?

  • A) Cellulitis
  • B) Lymphangitis
  • C) Type 4 hypersensitivity reaction – CORRECT
  • D) Tuberculosis

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CASE OUTCOME: CBC and CRP normal.  Case d/w ID.  Treated with ibuprofen and Zyrtec.  Got a little worse then gradually improved without antibiotics

 

 ACID Mnemonic

  • Allergic = Type I: reaction mediated by IgE antibodies.  Examples: bee sting, hives, anaphylaxis
  • Cytotoxic = Type II: cytotoxic reaction mediated by IgG or IgM antibodies.  Examples: Hemolysis, graft rejection
  • Immune Complex = Type III: reaction mediated by immune complexes.  Examples: Serum sickness, lupus
  • Delayed = Type IV: delayed reaction mediated by cellular response.  Examples: PPD, nickel, poison oak, vaccines