Designation for several severe forms of ichthyosis, present at birth, that are characterized by hyperkeratotic scaling. Infants may be born encased in a collodion membrane which begins shedding within 24 hours. This is followed in about two weeks by persistent generalized scaling. The forms include bullous (hyperkeratosis, epidermolytic), non-bullous (ichthyosis, lamellar), wet type, and dry type.