Contact Dermatitis (CD)


(Figure 3.13A-B, Tables 3-5 to 3-8)
  • Acute or chronic inflammatory reaction to a substance in contact with the skin; divided into irritant and allergic CD
  • Irritant contact dermatitis (ICD)
    • Accounts for 80% of CD
    • Due to direct local cytotoxic effect of irritant on skin
    • Acute ICD: acute exposure to toxic agent; presents with pruritus and sharply localized erythema with vesicles, edematous papules or hemorrhagic blisters, ± scaling or crusting; no distant spread
    • Chronic ICD: repeated exposure to mild irritants (low-grade irritation); presents with diffuse or localized but ill-defined scaly patches and plaques
  • Allergic contact dermatitis (ACD)
    • Accounts for 20% of all CD
    • Type IV delayed hypersensitivity to contactant (to which already sensitized), onset may be delayed as long as 24–96 h after allergen exposure
    • Nickel and poison ivy (urushiol) most common causes of ACD
    • Patch testing (Figure 3.13C) is the gold standard for diagnosing ACD; grading system:

         
       
      ReactionDescription
       
      +
       
      Weak reaction with erythema, infiltration, ± papules
       
      ++
      Strong reaction: vesicles, erythema, infiltration, papules
       
      +++
       
      Spreading bullous reaction
       
         

      • Poral reaction: non-allergic reaction due to cobalt residing in acrosyringium
    • Acute ACD: typically presents 24–48 h after exposure and presents with pruritus, vesicles, weeping and erythema, ± dissemination of lesions
    • Subacute ACD: presents with eczematous scaly plaques or lichenification correlating to areas of contact with allergen
  • Histology: spongiosis, intraepidermal vesicles and superficial perivascular infiltrate in acute setting; acanthosis, hyperkeratosis and mild superficial infiltrate in chronic setting
  • Treatment: avoid exposure irritants/allergens; topical corticosteroid, patch testing (for ACD), if severe may use short-term systemic corticosteroid
       
     
    FactorsACDICD
     
    Previous exposure required
     Yes No
     
    Immunologic reaction
     Yes No
     
    Distant spread
     Yes No
     
    Dose-related response
     No Yes
     
    Similar reaction in others w/ exposure
     No Yes
     
       
Figure 3.13 A: Allergic contact dermatitis (Courtesy of Dr. Paul Getz) B: Subacute contact dermatitis C: Patch testing, 2+ reaction (Courtesy of Dr. Sophie M. Worobec)
Figure 3.13
A: Allergic contact dermatitis
(Courtesy of Dr. Paul Getz)
B: Subacute contact dermatitis
C: Patch testing, 2+ reaction
(Courtesy of Dr. Sophie M. Worobec)

   
 
Table 3-5 Contact Allergens
Formaldehyde-Releasing Preservatives
 
Quaternium-15
Most common cosmetic preservative to cause ACD; personal care products
 
2-Bromo-2-nitropropane-1,3-diol (Bronopol)
Formaldehyde-releasing preservative in personal care products and variety of industrial applications
 
Diazolidinyl urea (Germall II)
 
Formaldehyde-releasing preservative; personal care products (especially bubble baths, baby wipes and household detergents)
 
Imidazolidinyl urea (Germall 115)
Formaldehyde-releasing antimicrobial preservative used in cosmetics
 
DMDM hydantoin
 
Formaldehyde-releasing antimicrobial preservative used in cosmetics like shampoo, hair conditioners and skin care products
Rubber accelerators
 
Thiuram
 
Rubber in shoes, rubber gloves, elastic, fungicides, paints, barrier contraceptives

{Thiuram cross reacts w/ disulfiram}
 
Mercaptobenzothiazole (MBT)
Most common cause of allergic shoe dermatitis
 
Rubber products, tires, antifreeze, anticorrosive agents, cutting oils, electrical cords, fungicides, rubber shoes (sneakers, tennis shoes, etc.)
 
Carba mix
Leather shoes, tires, fungicides, cosmetic applicators, gloves, adhesives, elastic, barrier contraceptives; may cross react with thiuram derivatives

{Repeated washing of elastic (ie. undergarments) with hypochlorite (bleach) causes elastic to become more allergenic (due to ↑ availability of carbamates), which may result in ‘elastic dermatitis’ or ‘bleached rubber syndrome’ (but patch test negative for rubber accelerators)}
 
Mercapto mix
Tires, elastic, rubber gloves, electrical cords, rubber soles of shoes, etc.
 
Black rubber mix
 
Heavy-use rubber products such as tires, hoses, cables and belts
 
Mixed dialkyl thioureas
Neoprene rubber (wetsuit), goggles, elastic, paint remover, shoe insoles
Textiles
 
Disperse blue 106
 
Clothing dye (bed linens, blue dye, clothing, tights, garment lining)
 
Ethylene urea melamine
formaldehyde mix
Permanent press clothing (wrinkle-resistant)

{Textile dermatitis typically occurs where clothing fits tightly (posterior neck, upper back, lateral thorax, axillae, waistband, flexor surfaces); ± purpuric contact dermatitis}
Adhesives
 
Epoxy resin (bisphenol A)
 
Glues, plastics, electrical insulation, paint and primer
 
Colophony (rosin, abietic acid)
Paper, cosmetics, paint, adhesives, waxes, chewing gum, used in baseball/ ballet/musical instruments to ↑ friction
 
Cyanoacrylate (methyl or ethyl)
 
Fast-acting adhesive (Super or Krazy Glue), liquid bandages, Dermabond
 
Ethyl acrylate
Artificial nail (adhesive)
 
Methacrylate (methyl or ethyl)
Adhesive, artificial nails, dental fillings/sealants, hearing aids, hard contact lenses, glue (bone cement) for artificial joints, acrylic denture material

{May diffuse through intact surgical glove and cause paresthesias (i.e. most commonly seen in either dentist or orthopedic surgeon)}
 
p-tert-butylphenol formaldehyde resin
Leather/rubber adhesive
Sunscreen components
 
Benzophenone-3
 
Sunscreens, rubber products, cosmetics
 
PABA (Padimate O)
Sunscreen (UVB)

{PABA ± cross react w/ sulfonamides, azo dyes, benzocaine, PPD}
 
Oxybenzone
Sunscreen (UVA)

{Oxybenzone: most common sunscreen agent to cause photoallergic contact dermatitis}
Corticosteroids
 
Tixocortol-21-pivalate
Group A (hydrocortisone acetate, prednisone, methylprednisolone)
 
Budesonide
Group B (triamcinolone acetonide, desonide, fluocinolone acetonide, fluocinonide, halcinonide)

{Budesonide also marker for some Gr. D steroids}
 
Hydrocortisone-17-butyrate
Group D (hydrocortisone-17-valerate/butyrate, clobetasone-17-butyrate clobetasol proprionate, betamethasone valerate/diproprionate)
Hair preparations
 
Paraphenylenediamine (PPD)
Permanent hair dye, ‘black henna’ (not natural henna from plant), photographic developer, printing inks, black rubber, temporary tattoos
 
ACD typically on eyelids/ear helices/hairline or hands

{May cross react with: PABA, sulfonamides (including thiazide and furosemide), para-aminosalicylic acid, benzocaine and procaine (ester anesthetics), azo dyes (temporary/semi-permanent hair dye, pen ink, coloring agent)}
 
Monothioglycolate
 
Permanent wave preparations; typically in glycerol monothioglycolate
 
Ammonium persulfate
Hair bleach, bleaching agent in flour
Others
 
Bacitracin
 
Topical antibiotic ointment, otic and ophthalmic preparations
 
Balsam of Peru
Naturally occurring fragrance material, found in topical medications
 
Benzalkonium chloride
 
Skin disinfectant (ophthalmic solutions), cosmetics
 
Benzocaine, tetracaine
Local anesthetic (ester)

{May cross-react with PABA, PPD, and sulfonamides}
 
Cobalt
Added to other metals to ↑ hardness; found in jewelry, buttons, cosmetics, hair dye, joint replacements, ceramics, enamel, cement, paint, and pottery
 
Cocamidopropyl betaine
Hair and bath products like shampoo (surfactant)
 
Ethylenediamine
Medical creams, antifreeze, paint

{Cross-reacts with hydroxyzine and aminophylline}
 
Euxyl K400
Cosmetic and household products (preservative)
 
Fragrance mix
 
Several components (cinnamic aldehyde), detects 70% fragrance allergies
 
Formaldehyde
Textile resins (wrinkle-free clothing), cosmetics, tissue fixative, embalming solution, paints, disinfectants, and medications
 
Gold
 
Jewelry, dentistry, electronics, treatment of certain diseases (RA, SLE, etc.)
 
Glutaraldehyde
Cold sterilization (medical/dental equipment), disinfectant, tan shoe leather
 
Lanolin (wool alcohol)
 
Cosmetics and some topical creams
 
Methylchloroisothiazolinone
(Kathon CG)
Preservative in cosmetics and shampoos (antibacterial properties)
 
Neomycin sulfate
 
Antibiotic ointment, hemorrhoidal cream, otic and ophthalmic preparations
  
Co-sensitivity often between neomycin and bacitracin
 
Nickel sulfate
Costume jewelry, buckles, and snaps; dimethylglyoxime test detects nickel (positive if turns pink); ± co-sensitivity seen with nickel and cobalt
 
Paraben mix
 
Cosmetics, topical medications, food, textiles, antiperspirants
 
Potassium dichromate
Cement, leather (footwear), plaster, wood finishes, green felt of card tables
 
Propylene glycol
 
Cosmetics, topical medications (vehicle), antifreeze
 
Thimerosal
Preservative in contact lens solution, vaccines, otic/ophthalmic solution, antiseptic

{↑ photosensitivity with piroxicam if patient with positive reaction to thimerosal}
 
Tocopherol acetate
 
Vitamin E
 
Toluene sulfonamide

{Also known as tosylamide sulfonamide formaldehyde resin}
Nail polish (typically appears as eyelid dermatitis or periungual dermatitis)
    
 
   


   
 
Table 3-6 Plant Allergens
 AllergenPlant (Common Name)Scientific Name
 
Urushiol (includes pentadecacatechol in oleoresin)
Poison ivy, poison sumac, poison oak

{May cross react with Japanese lacquer tree (sap), cashew tree, mango tree, Indian marking nut (black juice), Brazilian Pepper tree (sap), gingko (seed pulp)}
Family: Anacardiaceae
 
Genus: Toxicodendron; Species: Rhus
 
Sesquiterpene lactone
Chrysanthemum, ragweed, sunflower, artichoke, arnica, daisy, marigold, arnica

{Dermatitis may be airborne (face, neck) or direct contact (hands)}
Family: Asteraceae or Compositae

{May cross react with permethrin}
 
Primin
Primrose
Family: Primulaceae
 
Species: Primula obconica
 
Diallyl disulfide,
allylpropyl disulfide
Garlic, onion, chives
Family: Alliaceae
 
Genus: Allium
 
Allicin
Garlic, onion, chives
Family: Alliaceae
 
Genus: Allium
 
Tuliposide A
Peruvian lily
Family: Alstroemeriaceae
 
Tulip, hyacinth
Family: Liliaceae
 
d -Usnic acid
Lichens
Several genera including Parmelia
 
Colophony
(Abietic acid, rosin)
Pine tree (resin)
Family: Pinaceae
 
Species: Pinus species
 
Tea tree oil
(Limonene)
Ti or tea tree
Family: Myrtaceae
 
Species: Melaleuca alternifolia
 
3-carene
 
Turpentine
 
Family: Pinaceae
      
 
   

   
 
Table 3-7 Plant Irritants (ICD)
 IrritantPlant
 
Bromelin
Pineapple (Ananas comosus)
 
Calcium oxalate
 
Dumb cane (Araceae), daffodils (Narcissus spp.), hyacinth (Liliaceae), pineapple
 
Phorbol esters
(in milky latex)
Poinsettias, spurges, crotons (Euphorbiaceae)

{May cause temporary blindness if latex contacts eye}
 
Capsaicin
 
Chili peppers (Solanaceae)
 
Thiocyanates
(Allyl isothiocyanate)
Garlic (Alliaceae)
 
Black mustard and radish (Brassicaceae)
 
Protoanemonin
(Ranunculin)
 
Buttercups (Ranunculaceae)

{Causes intense linear vesiculation}
{Ranunculin converts to protoanemonin after plant injury}
    
 
   

   
 
Table 3-8 Pigment Reactions from Tattoos
 Tattoo ColorChemical
 
Black
 
Carbon, iron oxide
 
Blue
Cobalt
 
Brown
 
Ferric oxide
 
Green
Chromic oxide
 
Purple
 
Manganese
 
Red
Cinnabar (mercury sulfide), cadmium red
 
White
 
Titanium dioxide
 
Yellow
Cadmium sulfide
    
    
   
     
  
Most common allergic reaction seen from red tattoo pigment