The causes of dandruff are similar to the causes of baldness (see page 65), but a brief review will be made here because certain skin conditions should be added. Pityriasis simplex capitis is probably the most common cause, although no definite etiology has been established. Autoimmune disorders such as lupus erythematosus should be considered. Inflammatory disorders include ringworm (tinea capitis), impetigo, and seborrheic dermatitis. Idiopathic skin disorders such as psoriasis and lichen planus cause dandruff. These disorders can all be recalled by the same mnemonic that was applied in baldness, that is, HAIR.
· H—Hereditary lesions include eczema and psoriasis.
· A—Autoimmune includes lupus.
· I—Inflammatory diseases include ringworm, impetigo, and seborrheic dermatitis. I also stands for idiopathic and thus includes pityriasis simplex capitis.
· R—Radiation dermatitis
The workup of dandruff is similar to that of baldness (see page 65).