Allergic Contact Dermatitis (ACD) is a common inflammatory skin disorder resulting from a type IV delayed hypersensitivity reaction to environmental allergens. It accounts for nearly 20% of all contact dermatitis cases, posing a significant diagnostic and therapeutic challenge in dermatological practice (1). The condition arises when a sensitized individual’s immune system overreacts to specific exogenous agents after repeated exposure, leading to localized or disseminated eczematous eruptions (2). The prevalence of ACD varies worldwide, ranging between 1.7% and 6%, depending on occupational, cultural, and environmental factors (3). In India, the problem is magnified by widespread exposure to diverse allergens such as hair dyes, cosmetics, metals like nickel and chromium, rubber, and plant materials. The disease not only affects patients’ quality of life but also contributes to substantial socioeconomic burden due to chronicity and recurrence (4). Pathophysiologically, ACD involves two distinct phases—sensitization and elicitation. Upon initial contact, allergens (often low molecular weight haptens) bind to skin proteins, forming complete antigens. These are processed by Langerhans cells and presented to T lymphocytes, leading to immunological memory formation. Subsequent exposures trigger cytokine release and inflammation, resulting in the characteristic eczematous lesions (5). Clinically, ACD presents with erythema, vesiculation, and intense pruritus at the site of contact. Chronic or repeated exposure can lead to lichenification and secondary infections. The diagnosis cannot be reliably established by history and clinical examination alone; hence, patch testing remains the gold standard for identifying the causative allergens and confirming the diagnosis (6). This test provides crucial insight into the specific sensitizers responsible, allowing for tailored patient education, allergen avoidance strategies, and preventive interventions. Early recognition and elimination of the offending agent are critical for effective management. Patient education, protective measures, and appropriate pharmacologic therapy with corticosteroids or immunomodulators form the mainstay of treatment. Given the rising incidence of ACD due to increasing industrialization and cosmetic use, studies like this are essential to identify regional allergen patterns and assess their clinical relevance (7). Aim and Objectives: 1. To study the incidence of various allergens in patients of Allergic contact dermatitis. 2. To study age incidence among patients of Allergic contact dermatitis. 3. To study sex incidence among patients of contact dermatitis to various allergens. 4. To study association between duration of exposure of an antigen required for clinical manifestation of allergic contact dermatitis. 5. To find incidence of occupational and non-occupational causes of Allergic contact dermatitis. 6. To study the association of allergic contact dermatitis and atopy.

Study Design This was a cross-sectional observational study conducted in the Department of Dermatology, Venereology and Leprosy, Bapuji Hospital and Chigateri General Hospital, attached to J.J.M. Medical College, Davanagere, from November 2019 to October 2021. Source of Data Patients with suspected allergic contact dermatitis (ACD) attending the outpatient department of Dermatology were included in the study after obtaining institutional ethical clearance and informed written consent. Sample Size A total of 100 patients of suspected ACD were enrolled for the study. Selection Criteria Inclusion Criteria • Patients of all age groups and both genders. • Clinically suspected cases of Allergic Contact Dermatitis willing to undergo patch testing. Exclusion Criteria • Pregnant and lactating women. • Patients who had used systemic corticosteroids or immunosuppressants in the past two weeks. • Patients with concurrent bacterial or fungal skin infections. Method of Data Collection After obtaining consent, a detailed history was recorded, including: • Duration of complaints and exposure to chemicals, • Occupational and personal history, • History of atopy, • Previous treatments, • Comorbidities and recurrence patterns. A complete clinical examination was performed, documenting: • Morphology of lesions, • Extent and site of involvement, and • Clinical diagnosis based on presentation. Patch Test Procedure All patients were counselled regarding the procedure and patch-tested using the Indian Standard Series (ISS) supplied by Systopic Laboratories, New Delhi, and approved by the Contact and Occupational Dermatoses Forum of India (CODFI). • The kit contained 20 common allergens in preloaded syringes. • It was stored at 4–8°C and brought to room temperature 15 minutes before testing. • The upper back of the patient was cleaned with sterile gauze, and the patch test unit was applied on the interscapular region, avoiding the midline. • Each allergen was loaded into aluminium chambers (Finn chambers) using 2–3 mm of test material. • The chambers were gently pressed to ensure proper occlusion. Patches were kept in place for 48 hours. Patients were instructed: • Not to wet or rub the test area, • To avoid tight garments, strenuous activity, and scratching, • To report immediately if severe itching or irritation occurred. Reading and Interpretation • Patches were removed after 48 hours, and the first reading was taken 45–60 minutes later. • A second reading was recorded on Day 4 (72 hours). • Reactions were graded according to the International Contact Dermatitis Research Group (ICDRG) guidelines as: o (–) Negative o (?) Doubtful (faint erythema) o (+) Weak positive (erythema, infiltration, papules) o (++) Strong positive (erythema, vesicles) o (+++) Extreme positive (bullous reaction) o (IR) Irritant reaction Statistical Analysis The collected data were entered in Microsoft Excel and analysed using SPSS software version 20.0. • Descriptive statistics (mean, percentage) were used for quantitative data. • Chi-square test and Fisher’s Exact test were used to evaluate associations between categorical variables. • A p-value <0.05 was considered statistically significant.

A total of 100 clinically suspected cases of Allergic Contact Dermatitis (ACD) were studied over a period of two years. The observations and findings are summarized in the following tables. Table 1: Age and Sex Distribution of Patients Age Group (Years) Male (n=44) Female (n=56) Total (n=100) Percentage (%) <20 4 3 7 7.0 21–30 10 14 24 24.0 31–40 12 18 30 30.0 41–50 10 13 23 23.0 >50 8 8 16 16.0 Total 44 56 100 100.0 Interpretation: The highest incidence of ACD was observed in the 31–40 years age group (30%), with a female predominance (56%). In our study, out of the 100 cases participated of which, 51 were Male and 49 were Female. Male: female ratio 1.04:1 Table 2: Occupational Distribution of Patients Occupation Number of Patients (n=100) Percentage (%) Housewife 28 28.0 Labourer / Construction Worker 16 16.0 Student 12 12.0 Farmer 10 10.0 Hairdresser / Beautician 8 8.0 Office Worker 14 14.0 Others (Mechanic, Cobbler, etc.) 12 12.0 Total 100 100.0 Interpretation: Housewives constituted the largest group affected (28%), likely due to frequent exposure to household cleaning agents, detergents, and cosmetics. In our study, out of 100 participants 39 (39%) patients belong to occupational category and 61 (61%) patients belong to non-occupational category. Table 3: Site of Lesion Involvement Site of Lesion Number of Patients (n=100) Percentage (%) Hands 32 32.0 Face / Neck 20 20.0 Feet 12 12.0 Forearms 10 10.0 Trunk / Back 8 8.0 Scalp 6 6.0 Multiple Sites 12 12.0 Total 100 100.0 Interpretation: The hands were the most common site involved (32%), followed by the face and neck (20%), reflecting exposure-related patterns. Table 4: Morphological Types of Lesions Type of Lesion Number of Patients (n=100) Percentage (%) Erythematous papules and vesicles 30 30.0 Eczematous plaques 26 26.0 Lichenified lesions 20 20.0 Hyperpigmented patches 14 14.0 Mixed (multiple morphologies) 10 10.0 Total 100 100.0 Interpretation: Acute eczematous papulovesicular lesions were most common (30%), followed by chronic lichenified eczema (20%). Table 5: Patch Test Results Patch Test Result Number of Patients (n=100) Percentage (%) Positive 62 62.0 Negative 38 38.0 Total 100 100.0 Interpretation: Patch test positivity was observed in 62% of cases, confirming allergic etiology in the majority of clinically suspected ACD patients. Table 6: Distribution of Positive Allergens Among Patch-Tested Patients Allergen Number of Positive Cases (n=62) Percentage (%) Nickel Sulphate 18 29.0 Fragrance Mix 10 16.0 Potassium Dichromate 8 13.0 Paraphenylenediamine (PPD) 7 11.0 Cobalt Chloride 6 10.0 Neomycin Sulphate 5 8.0 Balsam of Peru 4 6.0 Colophony / Epoxy Resin 2 3.0 Total 62 100.0 Interpretation: The most common allergen identified was Nickel Sulphate (29%), followed by Fragrance Mix (16%) and Potassium Dichromate (13%) — consistent with common exposure sources like artificial jewellery, cosmetics, and cement.

Allergic Contact Dermatitis (ACD) is a T-cell mediated delayed-type hypersensitivity reaction resulting from repeated exposure to specific allergens in sensitized individuals. It continues to be a significant dermatologic concern worldwide, accounting for a large proportion of occupational and non-occupational skin disorders.8 The present study included 100 clinically suspected cases of ACD who underwent patch testing to identify the specific allergens responsible for sensitization. In the present study, the majority of patients belonged to the 31–40 years age group (30%), which is comparable to the findings of Singh et al., who reported maximum incidence between 30–40 years, reflecting the period of greatest exposure to environmental and occupational agents.9 The female predominance (56%) observed in this study correlates with the reports of Sharma et al., where women constituted 58% of cases, likely due to their frequent exposure to cosmetics, detergents, and jewelry.10 Hormonal factors and increased cosmetic use may also contribute to higher sensitization rates in women. In this study, housewives (28%) and labourers (16%) represented the most affected occupational groups. Similar observations were made by Kaur et al., who found household exposure to soaps, detergents, and cleaning agents as a major cause among women.11 Occupational ACD is common among construction workers due to exposure to chromates and cement, consistent with our findings where Potassium Dichromate was among the top allergens. The hands (32%) were the most frequently involved site, followed by the face and neck (20%). This is consistent with studies by Gupta and Ghosh, who reported hand eczema as the predominant manifestation of ACD, attributed to direct contact with allergens during daily activities.12 The involvement of exposed areas such as the face and neck is usually related to cosmetic allergens like Fragrance Mix and Paraphenylenediamine (PPD) found in hair dyes and perfumes. In our study, 62% of patients showed a positive reaction to the patch test, confirming allergic aetiology. This finding is in accordance with Rao et al., who reported a positivity rate of 60% among clinically suspected ACD cases.13 Patch test positivity depends on the test series used, duration of exposure, and population sensitization pattern. Among the allergens tested, Nickel Sulphate (29%) was the most common sensitizer, followed by Fragrance Mix (16%), Potassium Dichromate (13%), and PPD (11%). Similar results were reported by Sharma and Chakrabarti, who found nickel to be the predominant allergen in 26% of cases.14 Nickel exposure is ubiquitous through artificial jewellery, buttons, and household items, explaining its high frequency. Fragrance Mix was the second most common allergen, as also reported by Thyssen et al., who emphasized the increasing use of fragranced personal care products leading to sensitization.15 Potassium Dichromate allergy is commonly linked to cement exposure, affecting construction workers and masons, consistent with our occupational data. PPD sensitivity (11%) was particularly observed among individuals using hair dyes, which aligns with Uter et al., who reported PPD as one of the leading cosmetic allergens worldwide.16 The presence of Cobalt Chloride (10%) and Neomycin Sulphate (8%) in our study corresponds with findings from Garg et al., who observed similar rates among patients using topical medicaments and metal objects.17 Overall, the patch test proved to be a valuable diagnostic tool in identifying specific allergens and guiding preventive measures. The allergen distribution in this study largely reflects changing lifestyle patterns, occupational exposures, and cosmetic use trends in the Indian population. Regular surveillance and region-specific patch testing are essential to update standard allergen panels and enhance clinical diagnosis.

The present study highlights that Allergic Contact Dermatitis (ACD) is a common dermatological condition affecting individuals in their most productive age group, with a slight female predominance due to greater exposure to household and cosmetic allergens. The hands were the most frequently involved site, followed by the face and neck, reflecting direct exposure patterns. Patch testing proved to be an invaluable diagnostic tool, confirming allergen-specific sensitivity in 62% of patients. The most prevalent allergens identified were Nickel Sulphate, Fragrance Mix, and Potassium Dichromate, followed by Paraphenylenediamine (PPD) and Cobalt Chloride. These findings correlate with environmental, occupational, and lifestyle-related exposure common in the Indian population. Regular patch testing and patient education play a crucial role in identifying and avoiding causative agents, thereby preventing recurrences and improving quality of life. Region-specific allergen panels and periodic epidemiological studies are essential to monitor evolving sensitization trends and to guide effective preventive and therapeutic strategies.

1. Lachapelle JM, Maibach HI. Patch testing and prick testing: A practical guide. Berlin: Springer; 2013. 2. Fonacier L, Bernstein DI, Pacheco K, Holness DL. Contact dermatitis: A practice parameter. Ann Allergy Asthma Immunol. 2015;115(2):170–216. 3. Thyssen JP, Johansen JD, Linneberg A, Menné T. The epidemiology of contact allergy in the general population—Prevalence and main findings. Contact Dermatitis. 2007;57(5):287–99. 4. Duarte I, Lazzarini R, Kobata CM. Contact dermatitis in São Paulo, Brazil: evaluation of 3675 patients. Am J Contact Dermat. 2003;14(3):137–43. 5. Vocanson M, Hennino A, Rozières A, Poyet G, Nicolas JF. Effector and regulatory mechanisms in allergic contact dermatitis. Allergy. 2009;64(12):1699–714. 6. Johansen JD, Aalto-Korte K, Agner T, Andersen KE, Bircher AJ, Bruze M, et al. European Society of Contact Dermatitis guideline for diagnostic patch testing. Contact Dermatitis. 2015;73(4):195–221. 7. Sharma VK, Chakrabarti A. Common contact sensitizers in Chandigarh, India: Results of 2000 patients tested over 12 years. Contact Dermatitis. 1998;38(3):127–31. 8. Lachapelle JM, Maibach HI. Patch testing and prick testing: A practical guide. 3rd ed. Berlin: Springer; 2013. 9. Singh S, Singh U, Pandey SS. Patch testing in allergic contact dermatitis: Our experience in 100 cases. Indian J Dermatol Venereol Leprol. 2012;78(5):552–558. 10. Sharma VK, Chakrabarti A. Common contact sensitizers in Chandigarh, India: Results of 2000 patients tested over 12 years. Contact Dermatitis. 1998;38(3):127–31. 11. Kaur I, Singh G, Kumar B. Occupational allergic contact dermatitis among housewives in Punjab. Indian J Dermatol Venereol Leprol. 2002;68(3):137–138. 12. Gupta M, Ghosh S. Hand eczema and its association with contact allergens: A clinical and patch test study. Indian J Dermatol. 2014;59(4):409–412. 13. Rao GRR, Srinivas CR, Balachandran C. Patch testing in allergic contact dermatitis: Results of 200 patients. Indian J Dermatol Venereol Leprol. 2004;70(5):283–287. 14. Sharma VK, Chakrabarti A, Gautam RK. Changing trends of contact sensitization in Chandigarh. Contact Dermatitis. 2010;62(6):343–346. 15. Thyssen JP, Linneberg A, Menné T, Johansen JD. The epidemiology of contact allergy in the general population. Contact Dermatitis. 2007;57(5):287–299. 16. Uter W, Gefeller O, John SM, Schnuch A. Contact allergy to hair dye ingredients: Data from the IVDK 2007–2013. Contact Dermatitis. 2014;71(6):334–341. 17. Garg T, Sharma S, Mahajan VK, Mehta KS. Pattern of contact sensitization among patients with contact dermatitis in a tertiary care hospital of North India. Indian Dermatol Online J. 2017;8(5):336–341.