After one to two weeks, large, tense blisters typically develop on the red plaques, containing clear or blood-stained fluid. GP creates a histamine response that causes extreme relentless itching (pruritus). GP is characterized by flaring and remission during the gestational and sometimes post partum period. Usually after delivery, lesions will heal within months, but may reoccur during menstruation. Causes
Pathogenically, it is a type II hypersensitivity reaction where circulating complement-fixing IgG antibodies bind to an antigen (a 180-kDa protein, BP-180) in the hemidesmosomes (attach basal cells of epidermis to the basal lamina and hence to dermis) of the dermoepidermal junction, leading to blister formation as loss of hemidesmosomes causes the epidermis to separate from dermis. The immune response is even more highly restricted to the NC16A domain. The primary site of autoimmunity seems not to be the skin, but the placenta, as antibodies bind not only to the basement membrane zone of the epidermis, but also to that of chorionic and amniotic epithelia. Aberrant expression of MHC class II molecules on the chorionic villi suggests an allogenic immune reaction to a placental matrix antigen, thought to be of paternal origin. Recently, both IgA22 and IgE24 antibodies to either BP180 or BP230 have also been detected in pemphigoid gestationis. Risk
Pregnant women with GP should be monitored for conditions that may affect the fetus, including, but not limited to, low or decreasing volume of amniotic fluid, preterm labor, and intrauterine growth retardation.
Transient erythroblastopenia of childhood (TEC) is a slowly developing anemia of early childhood characterized by gradual onset of pallor. Signs and symptoms
Individuals with TEC have a median age of presentation of 18–26 months; however, the disorder may occur in infants younger than 6 months and in children as old as age 10 years. Because of the gradual onset of the anemia, children are often healthier than expected from their low hemoglobin levels. Cause
The cause of TEC is unknown, but it thought to be triggered by a viral infection. While rare cases have been attributed to infection with Parvovirus B19, the majority of cases are not related to Parvovirus infection. This is in contrast to transient aplastic crisis, seen in patients with hemoglobinopathies such as sickle cell disease, which is usually caused by Parvovirus infection. Diagnosis
Children typically present with a moderate normocytic anemia (usual range: Hemoglobin 5-8 g/dL) and reticulocytopenia. Mean corpuscular volume (MCV) is usually normal for age. Hemoglobin F levels are also typically normal. Prognosis
Most patients recover completely within 1–2 months. However many reported cases have lasted 18–24 months and longer. References
External links
ped/2279 at eMedicine