Image Gallery: Scabies incognito

Abstract

DEAR EDITOR, A 72-year-old man with type 2 diabetes was diagnosed with an unusual variant of scabies. The patient initially presented with pruritus and folliculitis-like lesions but eventually developed multiple necrotic ulcers (a, b). Ecthyma was suspected, and skin swabs revealed bacterial superinfection. However, topical and systemic antibiotics did not clear the lesions and he did not respond to topical corticosteroids. Biopsies were not diagnostic for vasculitis, ecthyma or reactive perforating collagenosis. Resemblance to a previous case of atypical scabies led to re-examination, and multiple scabies mites were identified. The clinical picture is unusual and was possibly due to treatment with potent topical corticosteroids.

Scabies surrepticius: An uncommon presentation of a common dermatosis

“…The term Scabies surrepticius has been recently introduced to encompass the various atypical presentations of scabies that can be mistaken for another dermatosis 2 . Subtypes of scabies surrepticius included not only crusted scabies, but also other variants: incognito, nodular, scalp‐related and other less common morphologies that mimic, clinically and/or histologically other dermatoses (such bullous pemphigoid, langerhans cell histiocytosis, mastocytosis, ecthyma, pityriasis rosea, prurigo nodularis, systemic lupus erythematosus and urticaria pigmentosa) 2–5 …”

“…In 1975, Orkin used the term of “scabies incognito” to describe the unusual clinical presentation of the mite infestation in patients treated with topical (or systemic) corticosteroids. Clinically, skin lesions seen in scabies incognito are not specific with diffuse crusted macules, papules, nodules and blisters 3,5 …”

“…Clinically, skin lesions seen in scabies incognito are not specific with diffuse crusted macules, papules, nodules and blisters. 3 , 5 …”

“…2 Subtypes of scabies surrepticius included not only crusted scabies, but also other variants: incognito, nodular, scalp-related and other less common morphologies that mimic, clinically and/or histologically other dermatoses (such bullous pemphigoid, langerhans cell histiocytosis, mastocytosis, ecthyma, pityriasis rosea, prurigo nodularis, systemic lupus erythematosus and urticaria pigmentosa). [2][3][4][5] Establishing the diagnosis of scabies in these individuals can be challenging. The International Alliance for the Control of Scabies (IACS) criteria for the diagnosis of scabies may be of great help in cases of surrepticious scabies.…”

Scabies: A comprehensive review and current perspectives

“…48 Modification of clinical picture, called as scabies incognito, can occur due to inappropriate use of topical steroids causing delay in diagnosis. 49 Severe eczematization can also occur ( Figure 4).…”