Subungual and ungual scabies: avoiding severe presentation in high-risk patients

Abstract

Scabies is a pruritic disorder caused by Sarcoptes scabiei var. hominis infestation of the skin. Transferred by close body contact, scabies is endemic within nursing homes and among poor and overcrowded populations. Crusted scabies is a severe form of disease, characterised by a large, thick, crusted eruption with significant mite infestation. We report a patient hospitalised with crusted scabies that had massive nail involvement. A 79-year-old female patient with multiple comorbidities and several recent prior scabies diagnoses presented with agitation and dystrophic fingernails; scabies mites were found embedded in and below the nail keratin. Aggressive treatment resulted in complete resolution, with notable improvements in mental status. Crusted scabies with nail involvement is extremely rare and may be more likely to develop from initially subclinical infestation sites. It is important to consider this potential presentation, as standard topical treatments may prove ineffective when there is deep nail involvement.

Drug eruption-like scabies surrepticius: an uncommonly described variant of scabies appearing in a non-classic clinical presentation

“…In addition, with regard to establishing a diagnosis of scabies, often other people who have been in close contact with the patient shall also have symptoms (such as itching) and mite-associated lesions [3,5,8,14,19,26,37]. This is especially important for individuals with a prolonged duration of their undiagnosed or misdiagnosed condition.…”

“…Similar to the patient of Adris et al, to the best of my knowledge, there are 6 other scabies patients who initially had been misdiagnosed as having an adverse drug reaction (Tables 2, 3), [1,8,19,[24][25][26][27]. Four of the reported individuals were identified by Dermatology Online Journal || Letter either "adverse drug reaction" or "drug eruption" in the title of the paper [1,19,25,27].…”

“…In addition, the lesions not only have a predilection to appear on the areola and umbilicus, but also can be found on areas covered by the patient's underwear such as the belt line, buttocks, genitalia, and groin [3,7]. Hyperkeratotic subungual lesions may be an unsuspected reservoir for persistent infestation in scabies patients with therapy-resistant or recurrent mite infestation [3,[8][9][10].…”

“…Indeed, the nomenclature scabies surrepticius was coined in 2017 to provide a term for the medical lexicon that encompassed all the non-classic clinical presentations associated with this mite [12]. Several subtypes of scabies surrepticius have been described (Table 1), [1,3,5,[7][8][9][10]; the patient of Adris et al exemplifies the uncommonly described drugeruption-like scabies surrepticius subtype [1].…”

“…Four of the reported individuals were identified by Dermatology Online Journal || Letter either "adverse drug reaction" or "drug eruption" in the title of the paper [1,19,25,27]. However, scabies masquerading as an adverse side effect from the medications that the patient was receiving was only mentioned in the case report section for three of the individuals [8,24,26]. Hence, it is possible that there are additional patients with this subtype of scabies surrepticius that have been described in the medical literature.…”