Lichen simplex chronicus, neurotic excoriation and nodular prurigo and their correlation with atopy: A case-control study

Background: Lichen simplex chronicus (LSC), nodular prurigo (NP), and neurotic excoriation (NE) are considered as psychogenic pruritus disorders. Atopic dermatitis (AD) is also classified by some as a psychocutaneous disorder to point out the influence of psychologic factors in its recurrence, persistence and precipitation. AD and psychogenic pruritus share many common features including immunohistology, clinical course and their psychiatry. The aim of this assay was to study the correlation between psychogenic pruritic disorders and atopy. Methods: Ninty-two patients with psychogenic pruritus, including 57 cases of LSC, 27 cases of NE and 8 cases of NP, were referred to us within a period of 18 months. The patients were studied in our private Dermatology-Psychiatry liaison Clinic in order to find out the correlation of those disorders with atopy. Ninty-two healthy individuals with no apparent dermatologic disoder were selected from the general population as controls. Patients were considered atopic if they had the history of dermatitis, asthma or hay fever with the typical age of onset, distribution, seasonal variation, and history of remission and recurrence. Atopy was investigated by physical examination and thorough history by completing a questionnaire containing all reported major and minor criteria in the literature. Results: Forty five out of 92 patients with psychogenic pruritic disorders (48.9%) were atopic which was significant in comparison with the control group (20.6%) (p<0.0001, odd ratio = 3.68 (3.29 – 4.24), and CI = 99%). Conclusion: This study showed that atopic state seemed to be more common in patients with psychogenic pruritic disorders.