Netherton syndrome is a severe, autosomal recessive form of ichthyosis associated with mutations in the SPINK5 gene. It is named after Earl W. Netherton (1910–1985), an American dermatologist who discovered it in 1958. Signs and symptoms
Netherton syndrome is characterized by chronic skin inflammation, universal pruritus (itch), severe dehydration, and stunted growth. Patients with this disorder tend to have a hair shaft defect (trichorrhexis invaginata), also known as "bamboo hair". The disrupted skin barrier function in affected individuals also presents a high susceptibility to infection and allergy, leading to the development of scaly, reddish skin similar to atopic dermatitis. In severe cases, these atopic manifestations persist throughout the individuals life, and consequently post-natal mortality rates are high. In less severe cases, this develops into the milder ichthyosis linearis circumflexa.Netherton syndrome has recently been characterised as a primary immunodeficiency, which straddles the innate and acquired immune system, much as does Wiskott–Aldrich syndrome. A group of Netherton patients have been demonstrated to have altered immunoglobulin levels (typically high IgE and low to normal IgG) and immature natural killer cells. These Natural Killer cells have a reduced lytic function; which can be improved with regular infusions of immunoglobulin (see Treatment); although the mechanism for this is not clear.Patients are more prone than healthy people to infections of all types, especially recurrent skin infections with staphylococcus. They may have more severe infections; but are not as vulnerable to opportunistic pathogens as patients with true Natural Killer cell deficiency-type SCID.
Diagnosis
Eosinophilic pneumonia is diagnosed in one of three circumstances: when a complete blood count reveals increased eosinophils and a chest X-ray or computed tomography identifies abnormalities in the lungs, when a biopsy identifies increased eosinophils in lung tissue, or when increased eosinophils are found in fluid obtained by a bronchoscopy (bronchoalveolar lavage fluid). Association with medication or cancer is usually apparent after review of a persons medical history. Specific parasitic infections are diagnosed after examining a persons exposure to common parasites and performing laboratory tests to look for likely causes. If no underlying cause is found, a diagnosis of acute or chronic eosinophilic pneumonia is made based upon the following criteria. Acute eosinophilic pneumonia is most likely with respiratory failure after an acute febrile illness of usually less than one week, changes in multiple areas and fluid in the area surrounding the lungs on a chest X-ray, and eosinophils comprising more than 25% of white blood cells in fluid obtained by bronchoalveolar lavage. Other typical laboratory abnormalities include an elevated white blood cell count, erythrocyte sedimentation rate, and immunoglobulin G level. Pulmonary function testing usually reveals a restrictive process with reduced diffusion capacity for carbon monoxide. Chronic eosinophilic pneumonia is most likely when the symptoms have been present for more than a month. Laboratory tests typical of chronic eosinophilic pneumonia include increased levels of eosinophils in the blood, a high erythrocyte sedimentation rate, iron deficiency anemia, and increased platelets.