Regarding the clinical features and epidemiology of scabies, all of the following are true EXCEPT:

Explanation

## Clinical Features of Scabies: Pruritus Timing ### Key Point: **Pruritus in scabies is WORSE at night (nocturnal), not during daytime.** This is a classic clinical pearl and a frequent NEET PG trap. ### Why Nocturnal Pruritus Occurs The female mite is more active at night when body temperature rises and the host is in a warm bed. This increased mite activity triggers a hypersensitivity response, causing intense itching that often prevents sleep. ### Correct Features of Scabies | Feature | Detail | |---------|--------| | **Causative agent** | *Sarcoptes scabiei* var. *hominis* — obligate human parasite | | **Host specificity** | Cannot survive on other mammalian hosts (species-specific) | | **Burrows** | Pathognomonic lesion; present in 50–80% of classical scabies | | **Incubation (primary)** | 3–6 weeks (sensitization phase) | | **Incubation (reinfection)** | 1–3 days (anamnestic immune response) | | **Pruritus timing** | **Nocturnal (worse at night)** — not daytime | | **Itch relief** | Scratching provides temporary relief but leads to secondary infection | ### High-Yield: **Nocturnal pruritus is a cardinal feature of scabies and is often the chief complaint.** Patients frequently report sleep disturbance and may have excoriation marks from scratching. ### Clinical Pearl: The **absence of nocturnal pruritus** should prompt reconsideration of the diagnosis — other dermatoses (atopic dermatitis, contact dermatitis) may present similarly but lack this temporal pattern. ### Warning: Do NOT confuse pruritus timing: - **Scabies** → worse at night (nocturnal) - **Atopic dermatitis** → can be worse at night but not exclusively - **Urticaria** → often worse in evening/night but not pathognomonic