Journal of Clinical and Diagnostic Research, 2018, Nov, Vol-12(11): WC01-WC04 1 1 DOI: 10.7860/JCDR/2018/28950.12274 Original Article Dermatology Section Various Clinical and Histopathological Patterns of Idiopathic Photodermatosis: An Observational Study INTRODUCTION Idiopathic Photodermatosis are a group of skin diseases caused by chronic exposure to Ultra-Violet Radiations (UVR). UVR are part of the electromagnetic spectrum, and are of special interest to dermatologists as many skin disorders are caused by these wavelengths. The UV range (200–400 nm) is subdivided into UVA (320–400 nm), which is not visible to human eyes; UVB (290-320 nm), often referred to as sunburn spectrum and is biologically most active wavelengths reaching earth surface and UVC (200 to 290 nm) [1]. UVB forms 1% of the UVR reaching the earth and is highly energetic, while UVA forms 99% of UVR reaching the earth and is lower in energy [2]. The effects on skin are due to various biochemical mediators like IL-1, IL-10, serotonin, histamine, by-products of arachidonic acid metabolism etc released from keratinocytes, mast cells and other inflammatory cells [3]. The immunological changes result from effects on Langerhans cells, suppressor and other subtypes of T cells and release of cytokines like IL-1 and IL-6 [4,5]. The morphology of skin lesions varies considerably ranging from micropapules or papules to violaceous papules or plaques and lesions may be hypopigmented, skin coloured or hyper-pigmented. Condition may be acute or chronic and common presenting symptoms are intense itching, local swelling, burning sensation, blister formation or even peeling of skin. The usual sites of lesions are photoexposed areas of neck, upper limbs and face. These lesions are usually benign but cause cosmetic concerns to patient. The most common type of idiopathic photodermatosis is PMLE. Other less common types are Actinic prurigo, Chronic actinic dermatitis, Solar urticaria and Hydroa vacciniforme. Histopathology depends on the age of the lesion and various patterns are spongiotic, lichenoid, psoriasiform or perivascular infiltrate [6,7]. PMLE which is most common type of idiopathic photodermatosis is common in the first three decades of life and females are more often affected than males. The mean age in females and males is 33 years and 35 years respectively [8]. The aim of this study was to study the clinical and histopathological patterns of photodermatosis and to correlate between the clinical and histopathological findings. MATERIALS AND METHODS In this cross-sectional observational study, 100 consecutive cases of photodermatosis attending the Department of Skin and VD of tertiary care hospital, North India over a period of two years from October 2014 to June 2016, were included after getting approval from ethical committee of our institution. All cases of idiopathic photodermatosis attending the dermatology clinic with fresh lesions irrespective of age, sex, associated diseases and who were not on treatment were included. All non- idiopathic photodermatosis cases due to metabolic disorders, genetic disorders and exogenous (drugs) and patients not willing to participate in the study were excluded. The clinical history like age, sex, duration of the disease, site of lesion, any associated systemic disease and history of drug intake etc were noted in a pre-tested and pre-designed proforma after taking informed and written consent. Diagnosis was established by history and clinical examination. Elliptical incisional biopsies under local anaesthesia were taken from well developed lesions under aseptic conditions after taking consent. RESULTS Age of the cases varied from minimum of 10 years to 70 years with average age being 41.5 years. Among them, 49% were males and 51% were females and all patients were divided into four age groups. Maximum number (20/51) of female patients presented in the age group 26-40 year while 14 female cases presented in the age group DIMPLE CHOPRA 1 , RAVINDER SINGH 2 , RK BAHL 3 , RAMESH KUMAR KUNDAL 4 , SHIVALI AGGARWAL 5 , AASTHA SHARMA 6 , AANCHAL SINGLA 7 Keywords: Polymorphic light eruption, Summer season, Ultraviolet radiations ABSTRACT Introduction: The idiopathic photodermatosis have different histopathological patterns, spongiotic pattern being the most common. Aim: To study the histopathological patterns of photodermatosis and to correlate between the clinical and histopathological findings. Materials and Methods: Hundered consecutive patients with lesions of idiopathic photodermatosis were included in this cross-sectional observational study. The clinical diagnosis was made and confirmed after thorough history, clinical examination and relevant investigations, including biopsy. Results: In this study 49 participants were male and 51 were female. Maximum number (20/51) of female patients presented in the age group 26-40 years while most male patients (16/49) presented in the age group of 56-70 years. Total 95% cases had lesions on photoexposed parts of upper limbs followed by neck involvement in 51% cases. The most common presenting symptom was itching, seen in 98% patients. Polymorphic Light Eruption (PMLE) was the clinical diagnosis in 97% cases. The most common histopathological pattern observed was Spongiotic pattern which was seen in 46% cases. Conclusion: While young females in the age group 26-40 year were more commonly affected, lesions were more common in men who were in the age group 56-70 year. Population in North India may be at greater risk because their skin is suddenly exposed to sun in spring and summer after the end of winter season. The PMLE was the most common subtype. Spongiotic pattern was the most common histopathological pattern found, followed by lichenoid pattern.