Cervical and postocciptal lymphadenopathy can also be seen, but this generally presents 2–4 days after the onset of the febrile phase.In rare cases, HHV-6 can become active in an adult previously infected during childhood and can show signs of mononucleosis. Cause
There are nine known human herpesviruses. Of these, roseola has been linked to two: human herpesvirus 6 (HHV-6) and human herpesvirus 7 (HHV-7), which are sometimes referred to collectively as Roseolovirus. These viruses are of the Herpesviridae family and the Betaherpesvirinae subfamily, underwhich Cytomegalovirus is also classified. HHV-6 has been further classified into HHV-6A and HHV-6B, two distinct viruses which share 88% of the same DNA makeup, with HHV-6B the most common cause of roseola.After infection, these viruses enter a latent phase. Roseola caused by HHV-7 has been linked to the ability of HHV-7 infection to reactivate latent HHV-6. Spread
After exposure to roseola, the causative virus becomes latent in its host but is still present in saliva, skin, and lungs. HHV-6 is thought to be transmitted from previously exposed or infected adults to young children by the shedding of virus through saliva. Even so, most cases of roseola are transmitted without known exposure. Diagnosis
The diagnosis of roseola is made clinically based on the presence of the two phases: fever and rash. Laboratory testing is seldom used as the results do not alter management of the disease.
For example, a contracted muscle will bruise more severely, as will tissues crushed against underlying bone. Capillaries vary in strength, stiffness and toughness, which can also vary by age and medical conditions. Low levels of damaging forces produce small bruises and generally cause the individual to feel minor pain straight away. Repeated impacts worsen bruises, increasing the harm level. Normally, light bruises heal nearly completely within two weeks, although duration is affected by variation in severity and individual healing processes; generally, more severe or deeper bruises take somewhat longer. Severe bruising (harm score 2–3) may be dangerous or cause serious complications. Further bleeding and excess fluid may accumulate causing a hard, fluctuating lump or swelling hematoma. This has the potential to cause compartment syndrome in which the swelling cuts off blood flow to the tissues. The trauma that induced the bruise may also have caused other severe and potentially fatal harm to internal organs. For example, impacts to the head can cause traumatic brain injury: bleeding, bruising and massive swelling of the brain with the potential to cause concussion, coma and death. Treatment for brain bruising may involve emergency surgery to relieve the pressure on the brain. Damage that causes bruising can also cause bones to be broken, tendons or muscles to be strained, ligaments to be sprained, or other tissue to be damaged. The symptoms and signs of these injuries may initially appear to be those of simple bruising.