Paraphenylenediamine: Blackening more than just hair.

Paraphenylenediamine is an important constituent of hair dye toxicity of which one could herald fatal complications such as rhabdomyolysis, renal failure, angioneurotic edema, and respiratory failure. We present a case of hair dye poisoning that presented with respiratory distress due to laryngeal edema and later developed trismus, subclinical tetany, apnea, and conduction abnormality on electrocardiogram. This case report highlights the need for a thorough toxicological review of the components of any ingested substance.