Definition: autosomal dominant disorder of skin cornification caused by a mutation of filaggrin characterized by fine, light gray scales that primarily involve the limbs and trunk and spare the intertriginous regions
Epidemiology: most common type of hereditary ichthyosis
Etiology: autosomal dominant inheritance; associated with atopic diseases
Epidermal hyperplasia and defective keratinocyte desquamation
Clinical features
Onset usually between 3 and 12 months of age
Lesions
Generalized fine, white scaling
Dry and coarse skin (xerosis): more common on extensor surfaces (skin folds are usually not affected)
Hyperlinearity of palms and soles (accentuated skin lines)
Symptoms generally worsen in winter and improve in summer
