Fungal infections such as ringworm can cause hair loss if they occur on the scalp, explains WebMD. When ringworm attacks the scalp, it first appears as a small pimple. As it grows in size, it leaves behind bald, scaly patches of skin.
Ringworm causes further baldness when it infects individual strands of hair, which become brittle and fall out, states WebMD. Itchiness, redness and inflammation characterize areas of the scalp affected by ringworm, and scaly patches of skin may ooze liquid. Skin-to-skin contact is a method of transmitting ringworm, which is highly contagious. Other methods include contact with infected animals and contaminated items. While ringworm can disappear on its own, anti-fungal treatments are effective.