Head lice are generally uncomfortable, but typically do not constitute a serious condition.[7] The most common symptom is itching of the head, which normally worsens 3 to 4 weeks after the initial infestation.[citation needed] The bite reaction is very mild, and it can be rarely seen between the hairs. Bites can be seen, especially in the neck of long-haired individuals when the hair is pushed aside. Swelling of the local lymph nodes and fever are rare.