Differentiate ectoparasitosis by lice and mites in terms of clinical presentation and diagnostic approach.

• A. Lice cause pruritus and visible lice/nits on hair; mites cause intense pruritus with burrows in webs; diagnosis by finding lice/nits or by skin scrapings showing mites/eggs
• B. Lice cause burrows in webs; mites cause visible lice
• C. Lice always involve nails; mites only affect scalp
• D. Lice infections present with fever; mites cause joint pain

Answer: (A)

The key idea is how the two parasites present and how we confirm their presence. Lice live on hair shafts and bites cause itching, often with visible signs: live lice or nits (eggs) attached to hairs. Because you can directly observe them on the scalp or hair, diagnosis is usually made by examining the scalp and using thorough hair combing to reveal the lice or nits.

Mites from scabies, on the other hand, burrow into the outer layers of the skin, producing a very intense itching that’s often worse at night. The classic clue is burrows in web spaces between fingers and other skin folds. Diagnosis isn’t based on finding lice; it’s based on detecting the mite, its eggs, or its fecal pellets in skin scrapings, or by visualization of the burrows with dermoscopy.

So the best description pairs lice with pruritus plus visible lice or nits and straightforward detection on hair, while mites (scabies) are linked to intense itching with burrows and require skin scrapings or dermoscopy to confirm. Fever or joint pain aren’t typical diagnostic features of these ectoparasitic infections.