A chickenpox rash looks like clumps of small red bumps, similar in appearance to insect bites, that develop into blisters, break open and scab over, according to KidsHealth. Chickenpox bumps usually first develop on the face, abdomen and back before spreading elsewhere.
Someone who has been infected with chickenpox can infect others even before the telltale rash appears, according to Mayo Clinic. Headaches, fatigue, appetite loss and fever are some symptoms that an infected individual may notice before the rash develops. Chickenpox is contagious until all of the blisters have completely scabbed over, which usually takes five to 10 days. In most cases, bumps only appear on the external skin surface, but in severe cases, chickenpox lesions can develop in the mucous membranes of the body.
Because the bumps caused by the chickenpox virus do not appear all at once, a patient may have new bumps, blisters and scabs all at the same time, explains Mayo Clinic. The rash caused by chickenpox is usually itchy.
Chickenpox is highly contagious and can be transmitted through direct contact with blisters or fluids as well as through the air via sneezes and coughs, states KidsHealth. The chickenpox vaccine is highly effective at preventing the disease.