There are no specific tests that can pinpoint Kawasaki disease, an autoimmune condition that causes inflammation of the small and medium sized blood vessels throughout the body. In 80% of cases, the condition manifests before the age of 5 and boys are 50% more likely to be affected than girls.
Diagnosis of Kawasaki disease typically involves obtaining a detailed history of the onset of symptoms and a detailed clinical examination.
According to the criteria for diagnosis of Kawasaki disease prescribed by the National Institute for Health and Clinical Excellence, the disease may be confirmed if the child has had fever with a temperature of over 38ËšC (100.4ËšF) for more than five days and has at least four of the following symptoms:
- Puffy eyes with red whites of the eyes and visible blood vessels
- Swollen fingers and toes and redness and peeling of the palms and soles of the hands and feet. This may be painful meaning the child is unable to walk or crawl about.
- Dry mouth with cracked lips and red and swollen tongue
- Characteristic rash that appears over the torso
- Swollen lymph nodes in the neck
Some other conditions with similar features to Kawasaki disease need to be ruled out before diagnosis is confirmed and these include:
- Measles - a viral infection typically characterized by fever and rash
- Scarlet fever - bacterial infection giving rise to fever and rash
- Adenovirus or enterovirus infections
- Toxic shock syndrome - a rare but severely life threatening bacterial infection
- Staphylococcal scalded skin syndrome
- Stevens-Johnson syndrome, a severe allergic reaction to medication that leads to rash and widespread inflammation
- Glandular fever affecting the lymph nodes and causing fever
- Meningitis that may cause a fever and rash as well as affecting the brain and spinal cord
- Polyarteritis nodosa
- Mercury allergy
Other clinical features of disease
Routine blood measurements such as white blood cell count may be obtained. In over half of children with the condition, the level of white blood cells is raised. The blood platelet count may also be raised and reach a peak within the second or third week of the disease manifesting. In addition, blood levels of sodium, enzymes, protein and lipids may be altered.
- Urine analysis may reveal the presence of white blood cells in urine
- Inflammatory markers such as the erythrocyte sedimentation rate and C-reactive protein may also be raised
- Heart imaging studies may be carried out such as an electrocardiogram to measure the electrical activity of the heart and an echocardiogram to view the structure and function of the heart and to check for aneurysms in the coronary blood vessels