Diagnosis of the poisoned patient can often be accomplished before toxicologic laboratory tests by obtaining a detailed history and directed physical exam. In this second of three articles, we will examine the toxicology clues revealed by the skin. Part 1 dealt with clues found in eyes, hair, nails, and tongue, and Part 3 will be on body fluids including saliva, sweat, urine, breath, vomit, and stool.



  • Arsenic

Arsenic-related Cancers

  • Bowen’s Disease (intraepithelial carcinoma in situ)
  • Basal cell carcinoma
  • Internal malignancies (lung, liver, esophagus, bladder)

Skin Color Changes (usually hyperpigmentation)

  1. Increased melanin production or deposition of abnormal pigment
    • “Raindrops on a Dusty Road” (As)
    • Addison’s Disease (tan, esp scars and flexion creases)
    • Melanosis (metastatic malignant melanoma)
  2. Differential diagnosis of “Gray Man” (slate gray, blue-gray, slate-blue)
    • Ag (Argyria), Hg, Bi, Pb, As, Au (Chrysiasis) intoxication
    • Amiodarone (more marked on sun-exposed skin)
    • Chemotherapy (fluorouracil)
    • Ochronosis (gray to brown external ears, sclerae)
  3. Red Man Syndromes (usually 2º vasodilation)
    • Redness non-pigmentary, usually blanches
    • Rapid infusion of vancomycin, NAC
      • Flushing from histamine release
    • Borate poisoning (“red lobster”)
    • Degreaser’s Flush (TCE + alcohol)
    • Disulfiram reaction
      • alcohol + metronidazole, sometimes cefazolin
      • alcohol + coprine mushrooms (“Tippler’s Bane)
    • Diff’l Dx of erythroderma: Toxic Shock Syndrome
  4. Blue Man Syndromes
    • Cyanosis
    • Methemoglobinemia
      • aniline dyes, nitrites, local anesthetics (benzocaine)
      • unlike jaundice, sclerae remain white!
    • Pseudocyanosis (faux bleu)
      • Skin staining by fabric dye
  5. Toxic jaundice
    • Hepatotoxins
      • Jaundice is late sign, delayed by days after intoxication
      • Acetaminophen, Amanita and Lepiota mushrooms
    • Hemolytic toxins (often oxidizing agents that also cause methemoglobinemia, esp in patients with G6P deficiency)
      • chlorates, dapsone
      • gases: arsine, stibine
      • Loxosceles (brown recluse) envenomation, esp in children
  6. Other cutaneous discoloration syndromes
    • Hemochromatosis (bronze hyperpigmentation)
    • Carotenemia (sclerae remain white)
    • Skin and clothing stains from paint and glue-sniffing
      • gold and silver most common

Pressure lesions (narcotics and sedative-hypnotics)

  1. Redness
    • early bruising or pressure lesion
    • persists > 20 minutes after pressure relieved
    • failure to blanche on pressure distinguishes from flushing
    • 2º pressure-induced epidermal ischemia, but lesions also form on non-dependent skin
  2. Imprints
    • pattern ecchymoses from objects lain upon
  3. Bullous (“Coma Bullae”)
    • Barbiturates
    • Benzodiazepines
    • Carbon monoxide
  4. Any pressure lesion: check for myoglobinuria and rhabdomyolysis

Vesiculobullous Lesions

  1. Mustard gas
  2. Sulfuric and other acids
  3. Antibiotics, ACEI’s
  4. Caterpillars (Puss caterpillar of Texas; tarantulas (urticating hairs)
  5. Pemphigus, bullous pemphigoid
  6. Poison Ivy (also maculopapular)


  1. Barbiturates, borates, methadone, colchicine
  2. Toxic Epidermal Necrolysis (antibiotics), Stevens-Johnson Syndrome
  3. Non-Toxic Dffl Dx of Desquamation: Toxic Shock, Kawasaki’s Disease, Staphylococcal Scalded Skin Syndrome

Petechiae, purpura, hematomas

  1. Non-blanching discolorations of skin
  2. Anticoagulant rat poisons
  3. Heparin (thrombocytopenia)
  4. Ergot (acral cyanosis → thrombosis & necrosis)

Acneiform Rashes (skin cysts, comedones: blackheads and whiteheads)

  1. Halogenated hydrocarbons (dioxin)
    • Case of Viktor Yuschenko, Ukraine
    • Yu-Cheng Oil Disease, Taiwan
    • Factory explosion in Seveso, Italy, 1986
  2. Cushing’s Syndrome
  3. Oral Contraceptives


  1. Common allergic reaction to therapeutic course of antibiotics and other medications rather than overdose
    • Examples: sulfa, diphenylhydantoin
    • May be accompanied by fever, eosinophilia, lymphadenopathy
  2. Allergic contact dermatitis
    • Type IV hypersensitivity reaction, cell-mediated
    • Examples: poison ivy, metals (Ni), thiurams (rubber)
    • May also be vesicular


  • Formication (EtOH), cocaine bugs

Summary: Mechanisms of dermal injury

  1. Oxidizing (concentrated hydrogen peroxide)
  2. Reducing
  3. Corrosive (acids, alkalis)
  4. Protoplasmic (HF)
  5. Dessicant
  6. Vesicant (nitrogen mustard)
  7. Thermal
  8. Cryogenic
  9. Staining
  10. Neoplastic (As)
  11. Immunologic (poison ivy, Ni)
  12. Defatting (gasoline)
  13. Vasodilatory (disulfiram reaction)
  14. 14. mechanical (excoriation)

Prepared by Dr. Dave Roberts, of the Hennepin Regional Poison Center.