Chickenpox symptoms are divided into two phases, namely the prodromal phase and the rash phase:

1. Prodromal phase. Infants and young children often have no symptoms or only mild symptoms, which may include mild fever, irritability, refusal to breastfeed, and the simultaneous appearance of rashes. Older children and adults may experience chills, mild fever, headache, fatigue, sore throat, cough, nausea, and loss of appetite. These symptoms last for one to two days before the rash appears.

2. Rash phase. The rash first appears on the trunk, then spreads to the face and limbs. It starts as red maculopapular rash, turns into papules within a few hours, and develops into vesicles. The vesicle fluid is initially clear but soon becomes cloudy, and itching often accompanies the vesicles. About a week later, the scabs fall off and heal, generally leaving no scars. However, if there is a secondary infection, pus-filled lesions may form, and scabbing and healing may take longer.

Chickenpox rashes are distributed centripetally, mainly located on the trunk and then the head and face, with fewer on the limbs. Some patients may also develop vesicles on mucous membranes such as in the mouth, throat, conjunctiva, and external genitalia, which break open to form ulcers. The chickenpox rash often appears in successive crops, so at the same site, maculopapular rash, vesicles, and scabs can be seen concurrently. Chickenpox is generally a self-limiting disease and tends to heal naturally within about ten days.

Children usually experience milder symptoms and rashes, while adults have more severe symptoms and are more prone to complications like chickenpox pneumonia. Individuals with lowered immune function are susceptible to disseminated chickenpox, where the rash may merge into larger vesicles. Infections during pregnancy can cause fetal malformations, premature birth, or stillbirth. If chickenpox occurs a few days before delivery, the newborn may contract neonatal chickenpox, which can be quite severe.