FPN – Allergic Contact Dermatitis

Sep 8, 2019 admin DA LIỄU 0

Allergic Contact Dermatitis

Aka: Allergic Contact Dermatitis, Contact Urticaria

II. Pathophysiology

  1. Only occurs in genetically predisposed person
  2. Agent specific immunologic cell-mediated response
    1. Requires sensitization
    2. Reaction can be induced by over 3000 chemical agents

III. Course

  1. Develops 24-48 hours after exposure (6 hours to 7 days)
    1. Can develop after years of continued exposure
  2. Resolves after 2-3 weeks

IV. Causes: Common

  1. Nickel (less expensive jewelry)
    1. Reaction occurs in 6% of persons exposed
    2. Consider Patch Testing for nickel allergy
    3. Nickel allergic patients can test jewelry for nickel
      1. Spot test is commercially available
    4. Consider irritant dermatitis from jewelry
      1. Remove Jewelry when washing hands
      2. Jewelry traps soap and lotions
  2. Black hair dye
  3. Topical medications
    1. Mycolog
    2. Neomycin
    3. Benzocaine
    4. Ethylenediamine
    5. Merthiolate (Thimerosal)
  4. Latex Allergy (10-17% of health care workers)
  5. Rhus Dermatitis (reaction in 70% of those exposed)
  6. Cosmetics (Fragrances and preservatives)
  7. Occupational exposures
    1. Potassium dichromate (cement, dyes, textiles)
      1. Welders
      2. Painters, dyers, leather tanners, lithographers
      3. Battery workers
    2. Epoxy resin (adhesives, electrical casings)
      1. High-tech workers (e.g. computers)
      2. Cable workers
      3. Pipe workers
    3. Rosin (adhesives)
    4. Rubber (thiuram, mercaptobenzothiazole, Carbamate)
    5. Surgery and cosmetic (acrylates: methyl methacrylate)
      1. Dentists and Dental Technicians
      2. Orthopedic surgeons
    6. Dyes
      1. Glyceryl monothioglycolate
      2. Para-phenylene diamine (in paint-on Tattoos)
  8. Sports participation
    1. See Sport-related Contact Dermatitis

V. Causes: Tattoo related reactions

  1. Topical antibiotic reaction (e.g. Neosporin)
  2. Dye reaction
    1. Mercuric Sulfide (Red): Irritant
    2. Cadmium (Yellow): Photo-reaction to sunlight

VI. Symptoms

  1. Severe Pruritus (early symptom)
  2. Mild Pain or Burning at dermatitis site

VII. Signs

  1. Marked erythema and edema
  2. Sharply demarcated lesion
  3. Distribution is single most important clue
  4. Numerous Vesicles
    1. Contrast with Pustules in Irritant Contact Dermatitis

VIII. Resources

  1. Haz-Map (Occupational Exposure Database)
    1. http://www.haz-map.com

IX. References

  1. Habif (1996) Clinical Dermatology, p. 84-94
  2. Lushniak (2000) Prim Care 27(4):895-916 [PubMed]
  3. Peate (2002) Am Fam Physician 66(6):1025-40 [PubMed]

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