Diseases beginning with the alphabet D:

Darier's disease
Dermatitis herpetiformis
Dermatofibroma
Dermatomyositis
Dermatosis papulosa nigra
Dermographism
Discoid eczema (go to nummular dermatitis)
Drug eruptions
Dry skin (go to xerosis)
Dysplastic naevi
Dysplastic moles (go to dysplastic naevi)