Generalised white patches on the skin usually mean vitiligo if there is no surface scale. In tropical countries also consider tuberculoid leprosy and pinta.
SIGN DIP MEN Overview of Hypopigmentation
S-Squamous Healing areas of eczema and psoriasis, Pityriasis alba, Pityriasis versicolor, Post discoid lupus erythematosus scarring, Tinea corporis,
I-Infective Pityriasis versicolor, Tuberculoid Leprosy, Pinta, Syphilis, Post herpes zoster
G-Granulomatous Sarcoidosis,
N-Neoplastic Morpheic Basal cell skin cancer, Epidermodysplasia verruciformis,
D-Drugs Phenols,
I-Immunological Vitiligo, Halo nevi, Localised Morphea, Lichen sclerosus, Scleroderma,
P-Physical Following liquid nitrogen, Post traumatic in dark skin, Idiopathic guttate hypomelanosis, Chronic radiodermatitis,
M-Metabolic
E-Endocrine
N-Nutritional
V Vascular Malignant atrophic papulosis
Other
Acquired White areas T cell lymphoma, Halo nevus, Lichen sclerosus, Malignant atrophic papulosis, Pinta, Post inflammatory hypopigmentation, Segmental vitiligo, Tinea versicolor, Vitiligo
Localised congenital depigmentation Nemonic is (WANT A DIP) of colour.
Wardenberg's, Alezandreni, nevus anaemicus, nevus depigmentosus, Tuberous sclerosus, Dyskeratosis congenita, Incontinentia pigmenti achromicans, Piebaldism.
