Scabies, caused by the mite Sarcoptes scabiei burrowing into human skin and causing intense itching, was endemic among soldiers of the Napoleonic Wars, where the overcrowded conditions of barracks, camp beds, and prisoner-of-war depots allowed the mite to spread rapidly. Soldiers commonly referred to scabies as 'the itch' and devised various ineffective remedies. The condition was both physically debilitating and socially stigmatising, as it was associated with filth and moral failure despite its entirely biological causation.

The scabies mite, like the body louse, appeared in the military literature of the Napoleonic era as a marker of the bodily degradation of warfare. Soldiers' memoirs and journals from the Peninsular War and the Russian campaign include references to 'the itch' alongside other bodily miseries. Later literary accounts of Napoleonic warfare, from Stendhal's Le Rouge et le Noir to Hardy's Dynasts, draw on the full spectrum of military suffering that included parasitic skin conditions. The mite's role in military suffering contributes, alongside the louse and the mosquito, to the parasite's persistent presence in war literature.