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Causes of cutaneous hyperpigmentation

Patchy hyperpigmentation of the skin is seen in 
  • Pellagra on exposed part to sunlight
  • Porphyria cutanea tarda
  • Scleroderma
  • Chloasma
  • Butterfly rash on face of sle
  • Acanthosis nigricans
  • Fixed drug eruptions
  • Drugs like Chlorpromazine, crofazimine,heavymetals like bismuth and gold
Acanthosis nigricans is a pigmented velvety thickening of skin
Types of Acanthosis nigricans
  • Benign type is seen in - Obesity, Cushing's syndrome, drugs-OCP, nicotinic acid, protease inhibitors
  • Malignant type seen in Internal malignancy
Megaloblastic anemia-hyperpigmentation of hands and face can be seen
Endocrine disorders
  • Addison's disease
  • Cushing's syndrome
  • Ectopic ACTH production.
  • Nelson's syndrome is seen in post adrenelectomy cases
Arsenic poisoning
Common causes of hyperpigmentation are
  • Familial, racial.
  • Sunburn. 
  • Addison'sdisease
  • Hemochromatosis
  • Peutz-Jeghcrs syndrome.
  • Chronic kala-azar.
  • clofazimine (red), busulphan.
  • Pellagra.
  • Chronic arsenical poisoning.
  • Facial pigmentation in chloasma or melasma. SLE
  • Porphyria (cutanea tarda) 
What are the sites examined for increased pigmentation :
  • Face.
  • Inside the oral cavity, specially cheeks and palate 
  • Palmar creases
  • General skin surface 
  • Pressure points
  • Normally pigmented area like areola
  • Sun exposed area
  • Recent scars
  • Palms and sole