What causes Riehl melanosis (pigmented contact dermatitis)?

Updated: May 27, 2021
  • Author: Elizabeth K Satter, MD, MPH; Chief Editor: William D James, MD  more...
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Answer

A variety of contact allergens have been implicated in pigmented contact dermatitis, as described below. [6, 7, 18] Although the majority of cases occur because of direct contact with these allergens, a few cases secondary to contact with airborne allergens have been described. [7, 19, 20]

Textile allergens are as follows:

  • Tinopal CH3566 - Optical whitener in washing powder

  • Napthol AS - Coupling agent for azo dyes

  • Biocheck 60 - Pesticide for textiles

  • PPP-HB - Textile finish

  • Mercury compounds - Bactericides

  • Formaldehyde - Preservative

  • Azo dyes - Dye [21]

  • Disperse Blue 106 - Dye

  • Disperse Blue 124 - Dye

  • CI Blue 19 (Brilliant Blue) - Dye

  • Rubber components

Cosmetic allergens are as follows [22] :

  • D&C Red 31 - Pigment

  • Brilliant Lake Red R - Pigment [23, 24]

  • D&C Yellow No. 11 and 10 - Pigment

  • PAN (phenyl-azo-2-napthol) - Impurity in azo pigments

  • Chromium hydroxide - Pigment

  • Carbanilides (trichlorocarbanilide and Irgasan CF3) - Bactericidal

  • Aniline dyes - Pigment

  • Hair dyes

  • Henna [25]
  • Ricinoleic acid (castor oil acid) - Bactericide (deodorants, lipstick, military camouflage) [26]

  • Kumkum (red) - Cosmetic powder and liquid (Hindu women) [27]

  • Fragrances

Fragrance allergens are as follows:

  • Jasmine absolute

  • Benzyl salicylate

  • Hydroxycitronellal

  • Ylang-ylang oil

  • Cinnamic alcohol

  • Musk ambrette [19, 28]

  • Cananga oil

  • Sandalwood oil

  • Synthetic sandalwood (containing bornyl methoxy cyclohexanol)

  • Geraniol oil

  • Eugenol

  • Isoeugenol

  • Balsam of Peru [29, 30]

  • Lavender oil

  • Lemon oil [31, 32]

  • Methoxycitronellal

  • Benzyl alcohol

  • Cinnamic derivatives

Miscellaneous allergens are as follows:

  • Chromate (K dichromate) - Leather, soaps

  • Nickel/nickel sulfate - Component metal products and jewelry

  • PTBPFR (paratertiary butyl-phenol formaldehyde resin) - Neoprene adhesive in leather products [33]

  • Plathymenia foliosa - Wood dust [20]

  • Minoxidil 5% - Topical vasodilator for hair loss treatment [34]


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