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contact dermatitis (exogenous eczema)

Classification: 1) allergic contact dermatitis 2) irritant contact dermatitis Etiology: 1) plants a) poison oak (allergic contact dermatitis) b) poison ivy c) poison sumac d) daffodil, pineapple, rhubarb, & century plants contain calcium oxalate [10] e) stinging nettle plant (Urtica dioica) are covered in tiny trichome hairs containing histamine f) phytophotodermatitis - Furocoumarins are the most common causative agents, found in limes (rhine), grapefruit, garden rue... 2) coral dermatitis 3) nickel (allergic contact dermatitis) [12] a) inexpensive pierced earrings b) belt buckles c) iPad [4] d) inexpensive jewlery 4) rubber a) sterile gloves b) shoes 5) soaps, fragrances, personal care products (allergic) 6) cleansers (irritant) 7) topical pharmaceutical agents a) cream & lotion preservatives: methylparaben b) lanolin c) topical antihistamines d) topical antimicrobials, especially neomycin, polymixin B, bacitracin e) topical local anesthetics f) transdermal patches 8) other a) paraphenylenediamine, a common ingredient in hair dyes, temporary black henna tattoos b) chromates, contained in cement c) solvents, surfactants d) acidic substances, alkaline substances (irritant) e) greases, tar, asphalt f) rubber Pathology: 1) allergic contact dermatitis - type-4 hypersensitivity reaction - prior exposure & immunologic sensitization to the causative agent must have occurred 2) irritant contact dermatitis - caustic or irritant effect of a chemical Clinical manifestations: 1) develops hours to days after contact with the offending agent - lasts for days to weeks. [13] 2) symptoms - pruritus - stinging & burning - pain 3) signs a) acute lesions: - pruritic papules & vesicles [12] - itchy red papules on a wound treated with topical antibiotic [15] - erythematous plaque covered with numerous small vesicles - vesicles can blister & ooze with eventual crusting [12] b) subacute lesions: - scaling, erythematous lesions without clear borders c) chronic lesions: - thick plaques with accentuated skin lines 4) distribution of rash may provide diagnostic clues - rash in distribution of where jewelry is worn (wrist, neck) suggests hypersensitivity to nickel [5] 5) lesions may be coin-shaped (coin-shaped jewlery containing nickel) 6) irritant contact dermatitis - inorganic acids & strongly alkaline substances may cause ulcerations - greases, tar, or asphalt may cause folliculitis - contact with crustaceans may cause eczema [10] * images [7,8,12,14] Special laboratory: 1) standard patch testing (gold standard) [10] 2) controlled application of suspected offending agent 3) cellulitis may complicate contact dermatitis Differential diagnosis: 1) atopic dermatitis 2) lichen simplex chronicus 3) nummular eczema a) lower legs (older men) b) fingers (younger female) 4) psoriasis 5) seborrheic dermatitis 6) photosensitivity reaction 7) chronic urticaria (occurs immediately & resolves quickly) Complications: - erythema multiforme from allergic contact dermatitis [10] - chronic allergic contact dermatitis can lead to hyperpigmented, lichenified plaques with painful fissures Management: 1) glucocorticoids a) topical glucocorticoid (local reaction) - use low potency (hydrocortisone, desonide) on face & neck [17] b) systemic: 1] systemic reaction or widespread skin involvement 2] prednisone 40-60 mg PO QD for 5-14 days, followed by cautious taper 2) antihistamines 3) avoidance 4) cool, wet compresses Follow-up: 1) lesions should be monitored for signs of secondary infection 2) counseling regarding avoidance of offending agent

Interactions

disease interactions

Related

common causes of allergic contact dermatitis patch testing

Specific

photoallergic contact dermatitis rhus dermatitis

General

eczematous dermatitis (eczema) type 4 hypersensitivity; T-cell-mediated (delayed) hypersensitivity

References

  1. Saunders Manual of Medical Practice, Rakel (ed), WB Saunders, Philadelphia, 1996, pg 924
  2. Medical Knowledge Self Assessment Program (MKSAP) 11, 16, 17. American College of Physicians, Philadelphia 1998, 2012, 2015 - Medical Knowledge Self Assessment Program (MKSAP) 19 Board Basics. An Enhancement to MKSAP19. American College of Physicians, Philadelphia 2022
  3. Usatine RP, Riojas M. Diagnosis and management of contact dermatitis. Am Fam Physician. 2010 Aug 1;82(3):249-55. PMID: 20672788
  4. Jacob SE and Admani S Case Report iPad - Increasing Nickel Exposure in Children. Pediatrics peds.2013-2871; July 14, 2014 PMID: 25022741 http://pediatrics.aappublications.org/content/early/2014/07/09/peds.2013-2871.abstract
  5. Leung DY et al. New insights into atopic dermatitis. J Clin Invest 2004 Mar 3; 113:651 PMID: 14991059
  6. Sasseville D Neomycin Dermatitis. 2010 Jan-Feb;21(1):3-7. PMID: 20137735
  7. Contact dermatitis (image) American Academy of Dermatology https://www.aad.org/public/diseases/eczema/contact-dermatitis - Mayo Clinic: Contact dermatitis (image) http://www.mayoclinic.org/diseases-conditions/contact-dermatitis/basics/definition/con-20032048
  8. Hogan DJ, James WD (image) Medscape: Allergic Contact Dermatitis http://emedicine.medscape.com/article/1049216-overview
  9. DermNet NZ. Contact dermatitis (no images) http://www.dermnetnz.org/dermatitis/contact-dermatitis.html
  10. Mattessich S, Finch J (images) Contact Dermatitis: An Overview Medscape. September 12, 2016 http://reference.medscape.com/features/slideshow/contact-dermatitis
  11. Spring S, Pratt M, Chaplin A. Contact dermatitis to topical medicaments: a retrospective chart review from the Ottawa Hospital Patch Test Clinic. Dermatitis. 2012 Sep-Oct;23(5):210-3. PMID: 23010827
  12. Contact Dermatitis: An Overview https://reference.medscape.com/slideshow/contact-dermatitis-6013071
  13. James W Fast Five Quiz: Urticaria (Hives) Medscape. December 12, 2022 https://reference.medscape.com/viewarticle/984987
  14. Finch J Contact Dermatitis: A Summary Medscape. Feb 6, 2023 https://reference.medscape.com/slideshow/contact-dermatitis-6013071
  15. NEJM Knowledge+ Dermatology - Nguyen HL, Yiannias JA. Contact Dermatitis to Medications and Skin Products. Clin Rev Allergy Immunol. 2019 Feb;56(1):41-59. PMID: 30145645 Review
  16. NEJM Knowledge+ Allergy/Immunology
  17. Fonacier L, Bernstein DI, Pacheco K, et al; American Academy of Allergy, Asthma & Immunology. Contact dermatitis: a practice parameter-update 2015. J Allergy Clin Immunol Pract. 2015;3:S1-39. PMID: 25965350