Which condition is caused by external parasites and is infestation of the scalp with head lice causing itching?

• A. Dermatitis Capitis
• B. Scalp Ringworm
• C. Pediculosis Capitis
• D. Tinea Capitis

Answer: (C)

The situation described is caused by external parasites living on the scalp—head lice. This specific infestation is called Pediculosis Capitis, and it leads to itching because many people develop an allergic reaction to the saliva lice inject when feeding on the scalp. That itching is the telltale sign of lice on the scalp.

Dermatitis Capitis is scalp inflammation from irritation or allergic reactions, not parasites. Scalp Ringworm and Tinea Capitis are fungal infections that cause itching and scales or patchy hair loss, but they’re caused by fungi, not insects. So Pediculosis Capitis best matches the idea of itching due to an external parasite infestation on the scalp.