Scabies-induced lichen simplex chronicus misdiagnosed as psychogenic pruritus: a case report

Lichen simplex chronicus has been defined as a localized skin condition characterized by thickening, hyperpigmentation and accentuated skin markings from chronic itching and from repeated scratching. The affected skin area is usually described as demarcated, and often circumscribed. It has even been defined as a "psychogenic pruritic disorder". The idea of a neurological component has also been suggested, hence the term 'neurodermatitis circumscripta'. However, the pathophysiology of this condition remains unclear. Several associations and etiologies have been reported in literature, including strong links with mental disorders-anxiety and obsessive compulsive disorder to be specific. We report this case, most importantly, to highlight the value of an open-minded approach to patients and the 'old-fashioned' physician character of empathy, the skill of detailed history taking and physical examination, and lastly to suggest that lichen simplex chronicus may not always present as a localized, 'circumscripta' or demarcated area of skin.

When a sixty-five year-old Caucasian female presented to our clinic agitated, intensely scratching her entire body and complaining of severe pruritus, an open-minded detailed approach during history taking and physical examination led to the working diagnosis of diffuse lichenification from chronic scratching secondary to a "possible" cutaneous disorder. Her medical history was unremarkable, but her psychiatric history was significant for Anxiety disorder. She remained on her anxiolytic medication. Her presenting symptom was reported to have persisted for more than 9 months. Review of previous unremarkable lab results and a remarkable findings on detailed skin inspection led to an empiric, trial regimen consisting of three topical preparations: an anti-pruritic-to break the itch-scratch cycle, anti-inflammatory-to curb any inflammatory/immune response and a 'last-ditch' scabicidal application. Follow-up was scheduled, but the patient called the office requesting an earlier follow up appointment. The lesions had significantly improved and the hyper-pigmented, indurated and escoriated skin appearance had resolved; and most importantly, the pruritus.

Thus we conclude that lichen simplex chronicus may not always present as circumscribed or localized area of skin as currently noted in literature. Also, in patients with psychiatric conditions including anxiety and obsessive-compulsive disorder in particular, effort should be made to avoid stereotyping their presentation as part of their mental disorder spectrum. The value of detailed history and physical examination, mixed with empathy is highlighted. We make our recommendation considering the profound turnaround in the patient's condition and quality of life after several months of emotional and psychological suffering.