Pediatric Contact Dermatitis Workup
- Author: Nanette B Silverberg, MD; Chief Editor: Dirk M Elston, MD more...
Patch testing may suggest or confirm the etiologic agent in allergic contact dermatitis. Laboratory studies are generally of little value in proving a diagnosis of contact dermatitis. However, they may be of value in eliminating some disorders from the differential diagnosis.
By placing standard concentrations of common allergens or specific ingredients of an implicated product on the skin and leaving them covered for 2 days, one may identify the allergen. If the patient has been previously sensitized to one of the agents under occlusion, this reexposure produces the elicitation phase of a type IV hypersensitivity reaction resulting in pruritus, erythema, and vesiculation.
Anaphylaxis may occur shortly after application of antigens used in patch testing. This finding is particularly true when testing for latex allergy but may occur with exposure to other antigens.
Monitor patients for anaphylactic reactions to antigens used in patch testing. Appropriate resuscitation must be available should anaphylaxis occur during the early stages of patch testing. Patch testing is contraindicated in the setting of angioedema and/or contact-induced anaphylaxis and should be avoided in patients with contact urticaria.
Atopic patients are more susceptible to irritant patch test reactions, especially when testing with metals. This may lead to false-positive results from routine patch testing. In a study of 101 sets of twins, no correlation was found between positive patch test results and atopy.
Dimethylgloxime (DMG) Spot Test
For patients with nickel allergy, a simple procedure exists to test jewelry for the presence of nickel. Trace amounts of nickel can be detected using the dimethylgloxime (DMG) spot test.
Two or 3 drops of 1% DMG and 10% hydroxide solution are placed on a white cotton-tipped applicator. The applicator tip is then rubbed against metallic areas of the jewelry. The appearance of a pink color on the applicator tip is a positive result and proof of the presence of nickel. This test is nondestructive. DMG test kits are inexpensive and available from many medical supply stores.
Biopsies are of little diagnostic help in contact dermatitis. Most types of contact dermatitis show very similar pathologic changes, and allergic and irritant contact dermatitis may not be distinguished with certainty in all cases. However, skin biopsy findings may serve to eliminate some conditions included in the differential diagnosis.
Histologic findings in contact dermatitis are not usually helpful in identifying the specific cause of the contact dermatitis. Findings in acute contact dermatitis include intercellular edema in the epidermis and vesiculation or blister formation.
Mast cells may be increased in urticarial reactions.
Chronic contact dermatitis shows signs of lichenification and varying degrees of nonspecific inflammation.
Lee PW, Elsaie ML, Jacob SE. Allergic contact dermatitis in children: common allergens and treatment: a review. Curr Opin Pediatr. 2009 Aug. 21(4):491-8. [Medline].
Militello G, Jacob SE, Crawford GH. Allergic contact dermatitis in children. Curr Opin Pediatr. 2006 Aug. 18(4):385-90. [Medline].
Fisher AA, Rietschel RL, Fowler JF. Fisher's Contact Dermatitis. 4th ed. Philadelphia, PA: Lippincott, Williams & Wilkins; 1995.
Silny W, Bartoszak L, Jenerowicz D, Zukiewicz-Sobczak W, Gozdziewska M. Prevalence of contact allergy in children suffering from atopic dermatitis, seborrhoeic dermatitis and in healthy controls. Ann Agric Environ Med. 2013 Mar 25. 20(1):55-60. [Medline].
Munivrana Skvorc H, Plavec D, Munivrana S, Skvorc M, Nogalo B, Turkalj M. Prevalence of and risk factors for the development of atopic dermatitis in schoolchildren aged 12-14 in northwest Croatia. Allergol Immunopathol (Madr). 2012 Dec 17. [Medline].
de Lagrán ZM, de Frutos FJ, de Arribas MG, Vanaclocha-Sebastián F. Contact urticaria to raw potato. Dermatol Online J. 2009 May 15. 15(5):14. [Medline].
Kennedy JL, Stallings AP, Platts-Mills TA, Oliveira WM, Workman L, James HR, et al. Galactose-a-1,3-galactose and Delayed Anaphylaxis, Angioedema, and Urticaria in Children. Pediatrics. 2013 Apr 8. [Medline].
Salvaggio HL, Scheman AJ, Chamlin SL. Shock Treatment: Swimming Pool Contact Dermatitis. Pediatr Dermatol. 2012 Nov 7. [Medline].
Clemmensen O, Hjorth N. Perioral contact urticaria from sorbic acid and benzoic acid in a salad dressing. Contact Dermatitis. 1982 Jan. 8(1):1-6. [Medline].
Brasch J, Geier J. Patch test results in schoolchildren. Results from the Information Network of Departments of Dermatology (IVDK) and the German Contact Dermatitis Research Group (DKG). Contact Dermatitis. 1997 Dec. 37(6):286-93. [Medline].
Warshaw E, Lee G, Storrs FJ. Hand dermatitis: a review of clinical features, therapeutic options, and long-term outcomes. Am J Contact Dermat. 2003 Sep. 14(3):119-37. [Medline].
Raikhlin-Eisenkraft B. Contact dermatitis from occupation-induced injury. Isr Med Assoc J. 2009 May. 11(5):322. [Medline].
Litvinov IV, Sugathan P, Cohen BA. Recognizing and treating toilet-seat contact dermatitis in children. Pediatrics. 2010 Feb. 125(2):e419-22. [Medline].
Fonacier LS, Aquino MR, Mucci T. Current strategies in treating severe contact dermatitis in pediatric patients. Curr Allergy Asthma Rep. 2012 Dec. 12(6):599-606. [Medline].
American Academy of Allergy, Asthma and Immunology; American College of Allergy, Asthma and Immunology. Contact dermatitis: a practice parameter. Ann Allergy Asthma Immunol. 2006 Sep. 97(3 Suppl 2):S1-38. [Medline].