An 11-year-old girl presents with a rash on her abdomen for the past month (Figure 131-1).

She denies other skin problems but her mother states that she had atopic dermatitis as a baby. The clinician readily identifies the problem as a nickel allergy to the nickel found in her belt buckle and jeans. He prescribes avoidance of nickel contact to the skin and prescribes 0.1 percent triamcinolone ointment to be applied twice daily until the contact dermatitis resolves. He describes various methods to cover medal snaps intense including sewing and fabric or painting clear nail polish over the metal. Neither method works 100 percent but it is hard to find jeans without metal snaps. The patient responded rapidly to treatment.^1,2

Contact dermatitis (CD) is a common inflammatory skin condition characterized by erythematous and pruritic skin lesions resulting from the contact of skin with a foreign substance. Irritant contact dermatitis (ICD) is caused by the non–immune-modulated irritation of the skin by a substance, resulting in a skin changes. Allergic contact dermatitis (ACD) is a delayed-type hypersensitivity reaction in which a foreign substance comes into contact with the skin, and upon reexposure, skin changes occur.³

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  Some of the most common types of CD are secondary to exposures to poison ivy, nickel, and fragrances.⁴

  
  
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  Patch testing data indicate that the five most prevalent contact allergens out of more than 3700 known contact allergens are nickel (14.3% of patients tested), fragrance mix (14%), neomycin (11.6%), balsam of Peru (10.4%), and thimerosal (10.4%).⁵

  
  
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  Occupational skin diseases (chiefly CD) rank second only to traumatic injuries as the most common type of occupational disease. Chemical irritants such as solvents and cutting fluids account for most ICD cases. Sixty percent were ACD and 32 percent were ICD. Hands were primarily affected in 64 percent of ACD and 80 percent of ICD⁴ (Figure 131-2).

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  CD is a common inflammatory skin condition characterized by erythematous and pruritic skin lesions resulting from the contact of skin with a foreign substance.

  
  
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  ICD is caused by the non–immune-modulated irritation of the skin by a substance, resulting in a skin rash.

  
  
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  ACD is a delayed-type hypersensitivity reaction in which a foreign substance comes into contact with the skin, and is linked to skin protein forming an antigen complex that leads to sensitization. Upon reexposure of the epidermis to the antigen, the sensitized T cells initiate an inflammatory cascade, leading to the skin changes seen in ACD.

History

Ask about contact with known allergens (i.e., nickel, fragrances, neomycin, and poison ivy/oak).

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  Nickel exposure is often related to the wearing of rings, jewelry, and metal belt buckles (Figures 131-3 to 131-5).

  
  
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  Lip licking—Saliva can cause an irritant contact dermatitis (Figure 131-6).

  
  
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  Fragrances in the forms of deodorants and perfumes (Figure 131-7).

  
  
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  Neomycin applied as a triple antibiotic ointment by patients (Figures 131-8 and 131-9).

  
  
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  Poison ivy/oak in outdoor settings. Especially ask when the distribution of the reaction is linear (Figures 131-10 and 131-11).

  
  
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  Ask about occupational exposures, especially solvents. For example, chemicals used in hat making can cause ICD on the hands (Figure 131-2).

  
  
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  Tapes applied to skin after cuts or surgery are frequent causes of CD (Figure 131-12).

  
  
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  If the CD is on the feet, ask about new shoes (Figures 131-13 and 131-14).