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Patch testing in hand and foot eczema: A prospective study at a tertiary care hospital

Hand and foot eczema is a common chronic, distressing skin condition with varying etiology. A patch test can be useful to confirm the presence of allergy and to identify the actual allergen. This study aimed to identify the common allergens causing hand and foot eczema with the help of patch testing . A total of 82 cases with hand and/or foot eczema underwent patch test using Indian Standard Series. Overall, the rate of positive patch test reactions reported in hand and foot eczema was 47.6%. Potassium bichromate was the common allergens in males and Nickel sulphate was the commonest allergen in females. The commonest presentation was chronic eczema in 51.22% and morphologically unspecified eczema (40.24%) followed by hyperkeratotic eczema was the most common. The rate of positive patch test reactions encountered was high. We suggest that patch test should be used to improve therapeutic outcome in hand and feet eczema .


Introduction
Eczema is a common, chronic inflammatory, distressing skin condition with a prolonged course, remissions, exacerbations and occasional resistance to treatment [1] . Hands and feet have a crucial role in day to day social life and at work, thereby individuals with hand and foot eczema often suffers from physical as well as psychological discomfort leading to deterioration of the quality of life [2] . The pathogenesis of hand and foot eczema is multifactorial, with a contribution of endogenous factors such as atopic dermatitis or exogenous factors such as contact dermatitis [3] . They are often associated with atopy and household or occupational exposure to allergens or irritants [3,4,5] . Therefore, identification and avoidance of the allergen, is important in the management of hand and foot eczema. Hence, patch testing is an important tool to confirm the presence of allergy and to identify the actual allergen. Majority studies in literature have focused on hand eczema [6][7][8][9][10][11][12][13] and few on foot eczema [4,5] . They have documented varying clinical pattern and different types of allergens as causative cause [4][5][6][7][8][9][10][11][12][13][14][15][16] . Depending on geographical, occupational, economic and social factors, allergen exposures may vary [8] . Hence this study was taken up to identify the common allergens causing hand and foot eczema with the help of patch testing in the geographical vicinity of Navi Mumbai.

Material and Methods
This was a prospective, cross-sectional study conducted in the out-patient department of dermatology at a tertiary teaching hospital in Navi Mumbai. The study was approved by the Institutional Ethics Committee. Informed consent was obtained from all participants included in the study. Between December 2014 and November 2015, a total of 82 adult patients with suspected hand and/or foot dermatitis irrespective of age and gender were included in the study. Patients less than 18 years, pregnant and lactating women, immune-compromised individuals, on systemic steroids or immunosuppressive agents and not willing to consent were excluded. Patients with fungal infections confirmed on direct microscopy were excluded before performing the patch test.
In every case, a detailed history was elicited and a thorough clinical examination was carried out. Attention was paid to the presenting associated symptoms, past history of allergy, occupational history, hobbies, seasonal variation, aggravating and relieving factors, habits, co-relation with usage of particular items (like cosmetics, jewelry, soaps etc.) and duration of eczema. The distribution of the lesions along with morphology of the eruption was recorded. Patients with fungal infections confirmed on direct microscopy were excluded before performing the patch test. All the patients with hand and/or foot dermatitis were patch tested using Indian Standard Series (ISS) approved by the Contact and Occupational Dermatoses Forum of India (CODFI) and marketed by Systopic laboratories (New Delhi, India), which consisted of 20 allergens. Allergens were put in Finn chambers and applied under occlusion to the back of each patient for 48 hours. Excessive hairs were shaved prior to application of the strip. Participants were advised to avoid any strenuous work and wetting of the application. Results were recorded at 48 hours (day 2) and 120 hours (day 5) after application of Finn chambers and graded as per the guidelines of the International Contact Dermatitis Research Group (ICDRG). An attempt was made to clinically classify the eczema as acute, sub-acute or chronic. A clinical diagnosis was also made for every patient. Data was entered in Microsoft-Excel (version 2010) and analyzed in SPSS software (version 20). Descriptive statistics were used to describe the results. Data were expressed in frequency, percentage and mean with standard deviation.

Entire sample
A total of 82 patients were included in this study. Out of the total, 60.97 % (50 patients) were males and 39.03% (32 patients) were females; the mean age was 36.7± 10.9 years (range 18 -65 years). The most common age affected group was 31-40 years (34.1%) followed by age group 21-30 years (25.6%). Majority by occupation were masons in males and housewives in females [ Table 1]. In this study, 14.6 % patients had a history of atopy, while family history of atopy was present in 4.9% patients.  Figure 1].

Hand eczema
Housewives and masons were the most frequently encountered occupations in subset of patients with hand eczema [ Figure 2]. 'Unspecified' was the most frequently encountered morphological variant of hand eczema. Palms/palmar surfaces (65.3%) followed by fingertips (57.1%) and dorsum of the hand (51%) were the commonest sites involved in hand eczema. In this study, 44.8% (22 out of 49) of the patients with hand eczema had a positive patch test. The most frequent positively encountered allergen in subset of hand eczema was Nickel (6 patients), followed by potassium bichromate (4 patients) [ Table 3].

Foot eczema
Housewives and farmers/semi-skilled workers were the most frequently encountered occupations in subset of patients with foot eczema. Chronic and hyperkeratotic were the commonest variants of eczema encountered [ Figure 3]. Dorsum of feet (90.4%) followed by sole (76.1%) were the most common sites involved in foot eczema. Overall, 38% (8 out of 21 patients) with foot eczema had a positive patch test. Mercaptobenzothiazole, black rubber mix and chlorocresol (2 patients each) were the common positively encountered allergens in the subset of foot eczema [ Table  3].

Hand and foot eczema
In patients with hand and foot eczema, the majority were males and mason by occupation. Pompholyx was the commonest morphological variant of eczema encountered. Overall, 75% (9 out of 12 patients) with hand and foot eczema had a positive patch test. Potassium bichromate (8 patients) was the most common positively encountered allergen in hand and foot eczema [ Table 3].

Discussion
Hand and foot eczema is common skin disorders caused by various exogenous and endogenous factors. Patch test has emerged as an important diagnostic tool in its management. The overall rate of positive patch test reactions reported in hand and foot eczema patients in our study was 47.6%. In this study, an attempt was made to identify the common allergens causing hand and foot eczema with the help of patch test and also to study the clinical pattern of hand and foot eczema in the neighboring vicinity of Navi Mumbai. In our study, overall male predominance was higher than female in hand and foot eczema, with male to female ratio of 1.56:1, which was similar to previous studies [4,9,10,[15][16][17][18][19][20] .
High male predominance could be due high exposure to more complex environment and occupational risk in the vicinity due to rapid urbanization. The most common affected age group was 31-40 years, followed by 21-30 years, which could be attributed to high occupational risk exposure and cosmetic item/jewelry usage. In this study, 14.6 % patients had a history of atopy, half of whom had positive patch test reactions. Family history of atopy was present in 4.9%, of two third patients showed positive patch test reactions. The presence of history of atopy was on the lower side in comparison to Vigneshkarthik et al. [8] and Handa et al. [15] study. Atopy has been usually considered the major cause of hand eczema [16] . The aggravating and relieving factors were known in 25.6% and only 4.9% patients had observed a seasonal variation in their symptoms. In this study, scaling (73.2%), followed by plaque (48.8%), xerosis (42.6%) and hyperpigmentation (40.2%) were the common skin manifestations. Chronic eczema (51.2%) was the commonest clinical variant of eczema encountered which was similar to previous studies [13,19] .

Hand eczema
Housewives and masons were the most frequently encountered occupations with hand eczema in this study, which are similar to finding of previous hand eczema in other Indian studies. [6,7,10,15] Females frequently come in contact with various detergents, soaps, chemicals and cosmetics which are predisposing factors in the development of hand eczema. Masons handle and work with cement which is a known contact sensitizer, without much protective measures and hence are more prone. Palms/palmar surfaces followed by fingertips were the commonest sites involved in patients with hand eczema. Other studies have demonstrated the involvement of dorsum of hand as the commonest site [9,19] . 'Unspecified' was the most frequently encountered morphological variant of hand eczema followed by hyperkeratotic and pompholyx type, which is similar to Handa et al. [15] , but was markedly different from majority of the previous hand eczema studies from India [7,8,9,15] . In this study, 44.8% of the total patients with hand eczema had a positive patch test, which was lower compared to previous Indian studies [8,21] . A significantly higher patch test positivity (48%-82%) has been reported by most Indian studies [6,7,9,10,15] . Nickel, followed by potassium bichromate was the most frequently encountered allergen, exclusively in hand eczema similar to Suman et al. [6] , Majid et al. [7] and Qayoom et al. [12] studies. None of our patients tested positive to fragrance mix. Other studies have demonstrated potassium bichromate as the commonest allergen in hand eczema [10,15] , followed by fragrance mix [15] and colophony [9] . Mehta et al. had the highest positive reactions with parthenium followed by fragrance mix and potassium bichromate in their study [13] .

Foot eczema
Housewives and farmers/semi-skilled workers were the most frequently encountered occupations with feet eczema ~ 73 ~ www.dermatologypaper.com in this study, which is similar to the findings of previous foot and leg eczema studies [5,18,19] . Dorsum of feet was the commonest site involved in our study corresponding to the shape of the footwear "V-shaped chapels", which is similar to findings of previous studies [4,5,14,18,19] . This type of footwear is usually worn without socks and is preferred by individuals living in hot and humid climate. Overall, 38% of the total patients with foot eczema had a positive patch test. The patch test positivity in our study was comparatively lower to most of the previous Indian studies which ranged from 46% to 88% [4,14,18,19] . Mercaptobenzothiazole, black rubber mix and chlorocresol were the common positively encountered allergens in foot eczema. Study by Priya et al. [14] documented Mercaptobenzothiazole, whereas Kumar et al. [18] documented Parthenium followed by Mercaptobenzothiazole to be the commonest agents to show positive patch reactions in foot eczema. These agents are usually used as footwear-chemicals or rubber-based adhesives in the foot wear industry and are apparently the cause of foot eczema.

Hand and feet eczema
Out of the total participants, 14% had eczematous lesions on hand and foot. Mehta et al. [13] reported hand and foot involvement as 10%, whereas Chowdhuri et al. have reported 18% [22] . Majority of patients with hand and foot eczema in this study were males and mason by occupation.
Pompholyx was the commonest morphological variant of eczema encountered. In this study, 75% patients with hand and foot eczema had a positive patch test. The patch test positivity in our study was quite high. However, due to paucity of data in the literature we were not able to compare this finding in this subset of patients. The patch test reaction was positive in majority for Potassium bichromates. Study by Chowdhuri et al. has documented potassium bichromateas frequent allergen in foot wear dermatitis [22] . The probable reasons for this higher incidence of Potassium bichromate sensitivity in our study could be due to the fact that the majority were mason by occupation, involved in cement /infrastructure work in the vicinity and may have inadequate protective measures/gears. Overall in the entire sample, the rate of positive patch test reactions reported in hand and foot eczema patients in this study was 47.6%. Potassium bichromate was the common allergens in males and Nickel sulphate was the commonest allergen in females in the entire sample. This observation was consistent with other studies [17,20] . In literature, a high positive rate of patch test and different types of allergens as causative cause is also documented (Table 4). Thus, we suggest that patch test should be used to improve therapeutic outcome in the management of hand and foot eczema. Also counseling the patients about possible occupational exposure, lifestyle modifications and preventive measures should be an integral part of its management.  [6] Hand eczema 67% Nickel Sulphate, Potassium Dichromate Majid I (2016) [7] Hand eczema 48.5% Nickel Sulphate, Potassium Dichromate Vigneshkarthik N et al. (2016) [8] Hand eczema 37% Nickel Sulphate, Para-Phenylenediamine, Potassium Dichromate Laxmisha C et al. (2008) [9] Hand eczema 52.78% Potassium Dichromate Kishore NB et al. (2005) [10] Hand

Limitation of the study
The sample size was limited; inclusion of larger sample size would have definitely increased the validity of the conclusions. In this study, Indian standard series was used which is standard for common allergens, but does not contain many allergens that may be relevant to hand and foot eczema; thereby individualized modifications should be considered.

Conclusion
In conclusion, hand and foot eczema has a variable clinical profile and etiology. The rate of positive patch test reactions reported in hand and foot eczema patients was 47.6%. Potassium bichromate and Nickel sulphate were the common allergens identified in the majority of patients. We suggest that patch test should be used to improve therapeutic outcome in the management of hand and feet eczema.