P-PHENYLENEDIAMINE

Other

30

Caution

CAS Number: 106-50-3

About P-PHENYLENEDIAMINE

A potent hair dye chemical — gives lasting dark colors but is one of the most common causes of severe allergic reactions to hair dye. EU-restricted with strict limits.

Detailed Analysis

p-Phenylenediamine (PPD, CAS 106-50-3, C₆H₄(NH₂)₂, CI 76060) is an aromatic diamine used as a primary intermediate in oxidative hair dyeing. It is one of the most potent contact sensitizers in common use — responsible for the majority of hair dye allergic reactions. EU Annex III/8a restricts its use to hair dye products only, with mandatory patch testing warnings. Sensitization rates in patch-tested dermatitis patients range from 4-7%. Cross-reactivity occurs with other para-amino compounds. Classified as a strong sensitizer (GHS H317) and suspected of causing genetic defects.

Known Concerns

  • ⚠ One of the most potent contact sensitizers in cosmetics
  • ⚠ EU restricted — Annex III/8a, hair dye only
  • ⚠ Can cause severe allergic dermatitis, angioedema
  • ⚠ Mutagenic potential — classified H341 (suspected genetic defects)
  • ⚠ Acute toxicity by ingestion
  • ⚠ Cross-sensitization with PABA, benzocaine, sulfonamides
  • ⚠ Mandatory patch testing required

Safety Score

30

Caution

Based on EU regulatory data, published safety research, and ingredient function analysis.

References

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EU CosIng Database

European Commission cosmetic ingredient registry

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This information is for educational purposes only and does not constitute medical advice. Always consult a healthcare professional for skin concerns or allergies.