Alternating and coexisting skin diseases: Are they real concepts?

Alternating and coexisting diseases.

Abstract

Background:  coexisting diseases are diseases that coexist with each other while alternating ones is the condition where one disease give place to another. In daily clinical practice, an increasing numbers of such conditions were seen. The exact pathogenesis is not fully understood.  Aim of the study: To find out if alternating and coexisting diseases are present in the clinical practice and to assess the frequency and various clinical aspects of common coexisting and alternating skin diseases among a sample Iraqi patients.  Patients and Methods: A cross sectional analytical study that was designed to include (4390) patients, with dermatological diseases regardless their types, but conditionally to be existed with two or more diseases, focusing on the main four entities namely psoriasis, vitiligo, lichen planus and alopecia areata. The period of the study extended from January 2019 until February 2020. The included patients were collected from dermatology outpatient clinic in Al-Sadr teaching hospital, Basra - Iraq. The patient were subjected to full medical history and physical examination, skin biopsy was done in suspicious cases to confirm the diagnosis. Results: From the total number of attendants to outpatient clinic, 53 patients have coexisting dermatological diseases, which constitute about 1.2% of the total, 62.3% of them were males, while 37.7%were females. The most frequent coexisting diseases were vitiligo and psoriasis which accounted for 28 (52.83%) of the total, followed by vitiligo and lichen planus which were 9 (16.98%), while psoriasis and lichen planus were 7 (13.2%), psoriasis and alopecia areata were 4 (7.55%), vitiligo and alopecia areata were 3 (5.67%) and finally lichen planus and alopecia areata were 2 (3.77%) of the total. Regarding the distribution of the cases according to the to their age, there is no significant statistical difference between males and females, p-value = 0.636, while according to onset of the first disease and second coexisting disease, there is significant statistical difference between males and females, p-value = 0.027, 0.001 respectively.  Conclusion: The frequency of alternating and existing diseases was 1.2% of the dermatological outpatient attendances. The most frequent combination was psoriasis and vitiligo, as they were reported in 28 (52.83%) of the total coexisting cases. Coexisting and alternating skin diseases are really present in clinical practice, although the exact pathogenesis is not well known, but we thought that one disease may trigger or alternate with others because they share immunological and or genetic predisposions so that another study on larger sample size and thorough immunological and genetic investigations is advisable to clarify this issue.