Ichthyosis Vulgaris: Most common form of ICHTHYOSIS characterized by prominent scaling especially on the exterior surfaces of the extremities. It is inherited as an autosomal dominant trait.Ichthyosis: Any of several generalized skin disorders characterized by dryness, roughness, and scaliness, due to hypertrophy of the stratum corneum epidermis. Most are genetic, but some are acquired, developing in association with other systemic disease or genetic syndrome.Ichthyosis, Lamellar: A chronic, congenital ichthyosis inherited as an autosomal recessive trait. Infants are usually born encased in a collodion membrane which sheds within a few weeks. Scaling is generalized and marked with grayish-brown quadrilateral scales, adherent at their centers and free at the edges. In some cases, scales are so thick that they resemble armored plate.Pycnodysostosis: Rare autosomal recessive syndrome characterized by delayed closing of CRANIAL SUTURES, short stature, ACRO-OSTEOLYSIS of distal phalanges, dental and MAXILLOFACIAL ABNORMALITIES and an increase in bone density that results in frequent BONE FRACTURES. It is associated with BONE RESORPTION defect due to mutations in the lysosomal cysteine protease CATHEPSIN K.Intermediate Filament Proteins: Filaments 7-11 nm in diameter found in the cytoplasm of all cells. Many specific proteins belong to this group, e.g., desmin, vimentin, prekeratin, decamin, skeletin, neurofilin, neurofilament protein, and glial fibrillary acid protein.Maxillofacial Abnormalities: Congenital structural deformities, malformations, or other abnormalities of the maxilla and face or facial bones.Cranial Fontanelles: Any of six membrane-covered openings between the CRANIAL SUTURES in the incompletely ossified skull of the fetus or newborn infant. The fontanelles normally close sometime after birth.Ichthyosis, X-Linked: Chronic form of ichthyosis that is inherited as a sex-linked recessive trait carried on the X-chromosome and transmitted to the male offspring. It is characterized by severe scaling, especially on the extremities, and is associated with steroid sulfatase deficiency.Dermatitis, Atopic: A chronic inflammatory genetically determined disease of the skin marked by increased ability to form reagin (IgE), with increased susceptibility to allergic rhinitis and asthma, and hereditary disposition to a lowered threshold for pruritus. It is manifested by lichenification, excoriation, and crusting, mainly on the flexural surfaces of the elbow and knee. In infants it is known as infantile eczema.Ichthyosiform Erythroderma, Congenital: 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.Proteus vulgaris: A species of gram-negative, facultatively anaerobic, rod-shaped bacteria that occurs in soil, fecal matter, and sewage. It is an opportunistic pathogen and causes cystitis and pyelonephritis.Skin: The outer covering of the body that protects it from the environment. It is composed of the DERMIS and the EPIDERMIS.Steryl-Sulfatase: An arylsulfatase with high specificity towards sulfated steroids. Defects in this enzyme are the cause of ICHTHYOSIS, X-LINKED.Desulfovibrio vulgaris: A species of gram-negative, anaerobic, rod-shaped bacteria isolated from soil, animal intestines and feces, and fresh and salt water.Hyperkeratosis, Epidermolytic: A form of congenital ichthyosis inherited as an autosomal dominant trait and characterized by ERYTHRODERMA and severe hyperkeratosis. It is manifested at birth by blisters followed by the appearance of thickened, horny, verruciform scales over the entire body, but accentuated in flexural areas. Mutations in the genes that encode KERATIN-1 and KERATIN-10 have been associated with this disorder.Acne Vulgaris: A chronic disorder of the pilosebaceous apparatus associated with an increase in sebum secretion. It is characterized by open comedones (blackheads), closed comedones (whiteheads), and pustular nodules. The cause is unknown, but heredity and age are predisposing factors.