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 Table of Contents  
ORIGINAL ARTICLE
Year : 2019  |  Volume : 3  |  Issue : 1  |  Page : 62-67

Foot eczema and footwear dermatitis: Role of patch test using Indian standard series and footwear series


1 Department of Dermatology, St. John's Medical College, Bengaluru, Karnataka, India
2 Department of Dermatology, Rajagiri Hospital, Aluva, Kerala, India

Date of Web Publication14-Feb-2019

Correspondence Address:
Vijay Aithal
Department of Dermatology, St. John's Medical College, Bengaluru, Karnataka
India
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Source of Support: None, Conflict of Interest: None


DOI: 10.4103/CDR.CDR_4_18

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  Abstract 


Context: Foot eczema is a common complaint encountered in dermatology outpatient department. Footwear dermatitis forms an important exogenous cause of foot eczema. Patch testing helps in identifying possible allergens causing footwear dermatitis. Aims: This study aims to study the clinical profile of foot eczema and to evaluate patch test results in these patients. Subjects and Method: Fifty patients with foot eczema were included in the study and underwent patch testing with Indian standard series and footwear series. Patch test results were read as per International Contact Dermatitis Research Group guidelines. Statistical Analysis Used: Descriptive data are given as mean standard deviation. Differences between patients were assessed by unpaired “t”-test and frequency of parameters by the Chi-square test. Linear regression analysis was used, and correlation coefficients were calculated by Pearson's method. P <0.05 was considered statistically significant. Results: Foot eczema was most common in the 18–29 years of age group (48%), with a male:female ratio of 1.78:1. Office workers (50%), followed by students (24%) were the common occupational groups affected. Allergic contact dermatitis (ACD) (60%), followed by discoid (10%) and forefoot eczema (10%) were the common morphological types. Parthenium (13.8%), diphenylguanidine (10.3%), and potassium dichromate (10.3%) were common allergens seen. Parthenium was the most common allergen identified by patch testing in our study. Conclusion: Patch testing may be used as a valuable and safe additional tool to aid the clinician's diagnosis and help in the treatment of ACD.

Keywords: Allergic contact dermatitis, eczema, patch test


How to cite this article:
Aithal V, Jacob MA. Foot eczema and footwear dermatitis: Role of patch test using Indian standard series and footwear series. Clin Dermatol Rev 2019;3:62-7

How to cite this URL:
Aithal V, Jacob MA. Foot eczema and footwear dermatitis: Role of patch test using Indian standard series and footwear series. Clin Dermatol Rev [serial online] 2019 [cited 2019 Oct 22];3:62-7. Available from: http://www.cdriadvlkn.org/text.asp?2019/3/1/62/252306




  Introduction Top


Foot dermatitis refers to the exclusive or predominant involvement of feet in an eczematous process. Legs and feet are affected by different types of eczemas. It may be the result of endogenous factors such as atopic dermatitis or exogenous factors such as contact dermatitis. Allergic contact dermatitis (ACD) in India varies from 1.7% to 6%. However, its true incidence is difficult to predict due to several factors such as demographic profile of patients, local industrial development, and index of suspicion in physician and availability of patch testing. Shoe dermatitis is a type of contact dermatitis resulting from exposure to various chemicals in a shoe and other factors such as sweating, heat, pressure, and friction which influence it. Foot dermatitis causes discomfort, embarrassment due to its location, interferes with activities of daily living and work and decreases quality of life.

The objective of our study was to study clinical profile of foot eczema and to evaluate patch test results in patients with foot eczema.


  Subjects and Methods Top


Fifty patients presenting to the Department of Dermatology in a tertiary care hospital in Karnataka, India, from January 2014 to April 2015 were included in the study. All the patients included in the study had eczema, exclusively or predominantly involving the foot, as determined by a senior dermatologist [Figure 1].
Figure 1: Forefoot hyperkeratotic eczema

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Patients with widespread dermatitis such as airborne contact dermatitis, pregnant or lactating patients, on long-term steroids (≥20 mg of prednisolone and/or cannot be stopped for 2 weeks) and who had lesions present at the patch test site were excluded. Ethical clearance was obtained from the Institutional Ethics Committee. Patient's written informed consent for participating in the study and photograph of the foot eczema was taken. A detailed history regarding demography, occupation, age at onset, site of initial lesion, extent, duration of disease, seasonal variation, symptoms, aggravating factors, type of footwear, history of atopy, history, and family history was taken with the help of a questionnaire. A complete general physical examination and cutaneous examination was carried out regarding nature, extent and morphology of lesions, with the help of a questionnaire. Relevant investigations such as potassium hydroxide, skin biopsy were done in necessary cases to rule out close differentials like psoriasis. Patients were subjected to patch testing using Indian standard series and footwear series as approved by Contact and Occupational dermatitis Forum of India, after obtaining informed consent.

Patch test results were read at 48 h, immediately after removing patch test (to exclude irritant contact reaction) and after 30 min. Third reading was taken after 96 h, using the International Contact Dermatitis Research Group guidelines [Figure 2] and [Figure 3].
Figure 2: Patch test with antigens in place

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Figure 3: 3+ Positive patch test result

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  Results Top


A total of 50 cases of foot eczema between 18 and 65 years (mean 34.78 ± 14.102) were diagnosed and included in the study. All the above 50 cases also underwent patch testing. There were 32 males and 18 females, with a male to female ratio of 1.78:1. All age groups were involved, and most of the patients were between 18 and 29 years (n = 24; 48%). However, there was no statistically significant difference between the various age groups (P = 0.907). Foot eczema was seen most among office workers (n = 25, 50%) followed by students (n = 12, 24%). Farmers (n = 2, 4%), homemakers (n = 8, 16%), and daily wage laborers (n = 3, 6%) were also affected.

Initial site of involvement

The dorsa of foot seen in 35 (70%) patients, was the most common initial site of foot eczema, followed by toes in 7 (14%) and medial aspect of foot, in 4 (8%). Forty-five out of 50 patients (90%) had bilateral involvement. Itching was the most common symptom, present in all the patients, followed by scaling in 49 (98%) and oozing in 14 (28%).

Most of the patients, i.e., 37 (74%) had eczema for more than 1 year at presentation. Twenty-five (50%) of the patients reported seasonal exacerbation of eczema, out of which 18 (36%) felt that their symptoms increased during winters, while the remaining gave a history of summer exacerbation 7 (14%).

Aggravating factors

The most common aggravating factor was detergents seen in 16 (32%) patients, followed by socks in 12 (24%) and plants in 5 (10%). The most common plant implicated was Parthenium.

Atopy was seen associated with juvenile plantar dermatitis, lichen simplex chronicus (LSC), forefoot eczema, and ACD. Hyperhidrosis was a common complaint in patients with ACD (23.3%), forefoot eczema (40%), and discoid eczema (40%).

Footwear worn by patients in our study could be broadly divided into three categories – V-shaped sandals, broad sandals, and shoes. Twenty-eight (56%) patients wore broad sandals whereas 16 (32%) patients had V-shaped sandals [Table 1]. Most of the patients examined wore leather footwear (n = 25, 50%) followed by rubber (n = 24, 48%) and canvas (n = 1, 2%).
Table 1: Correlation between design of footwear and the morphological type of eczema

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In our study, it was seen that across all the age groups, ACD was the most common type of foot eczema, with 11 (45.8%) in 18–29 years of age group, 11 (68.7%) in 30–49 years of age group and 8 (80%) in 50–65 years of age group. In the 18–29 years of age group, forefoot eczema was seen in 5 (20.8%) patients followed by juvenile plantar dermatosis in 3 (12.5%) and discoid eczema in 3 (12.5%) patients. In 30–49 years of age groups, discoid eczema (12.5%) and LSC (12.5%) were common. In 50–65 years of age groups, hyperkeratotic (10%) and asteatotic eczema (10%) were common. However, the difference did not seem to be statistically significant (P = 0.123).

The most common type of eczema in both males and females was ACD, 21 (65.6%) and 9 (50%) patients, respectively. Forefoot eczema and hyperkeratotic eczema were exclusively seen in males, whereas cumulative irritant contact dermatitis and asteatotic eczema was more common in females. However, the difference did not seem to be statistically significant (P = 0.123).

Positive allergens by patch test

Out of a total of 50 patients, 30 had positive patch test results, out of which 21 (70%) were males and 9 (30%) were females. Out of 30, 18 (60%) were office workers by occupation, 4 (13.3%) were students, and 3 of them were homemakers (10%).

The most common antigen detected to be positive was Parthenium seen in 8 patients (13.8%) [Figure 4] followed by diphenylguanidine, mercaptobenzothiazole (both constituents of rubber) [Figure 5], and potassium dichromate (constituent of leather), each seen in six patients (10.3%). Paraphenylenediamine (PPD) [Figure 6] and black rubber mix [Figure 7] were also common allergens seen in our study, each seen in 4 patients (6.9%) [Table 2].
Figure 4: Allergic contact dermatitis to Parthenium

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Figure 5: Allergic contact dermatitis to mercaptomix

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Figure 6: Allergic contact dermatitis to paraphenylenediamine

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Figure 7: Allergic contact dermatitis to black rubber mix

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Table 2: Allergen positivity among patients with positive patch test results

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Among those patients who showed a positive patch test result (n = 30), 14 showed positivity to a single antigen, 7 to two antigens, 6 to three antigens and 3 to four antigens. Thus, the total number of patch test positive results was 58. We analyzed the patch test results of patients against the morphological type of eczema they presented with [Table 3]. An analysis of positivity in patch tests to antigens of leather footwear (like potassium dichromate) and rubber footwear (like black rubber mix) against the actual footwear used by the patient, for most period of the day and most commonly worn by the patient, at the time of presentation, was made. Since most of the patients wore leather, rubber or canvas footwear, we analyzed only these antigens. Of the 30 positive patch test patients, 12 were clinically diagnosed to have ACD and the remaining 18 were non-ACD. Of the 20 negative patch test patients, 7 were diagnosed clinically as ACD, and the rest 13 were non-ACD. Thus, the sensitivity of patch test was found to be 58.10% and specificity 36.8%. The positive predictive value of patch test was 60; negative predictive value was 35, with an accuracy of 50%. This was statistically significant (P = 0.043) [Table 4].
Table 3: Patch test positivity amongst the different morphological types of foot eczema

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Table 4: Sensitivity and specificity of patch test with positive predictive value and negative predictive value

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  Discussion Top


Foot eczema is a common dermatological complaint, which leads to significant morbidity and psychosocial consequences. Patch testing is the diagnostic test of choice for identification of allergen in cases of ACD, which forms a major bulk of the foot eczemas. Our study makes an attempt at describing the various clinico etiological profiles of foot eczema and correlating them with patch test results.

Our study included 50 patients with foot eczema. Majority of the patients were young, in the age group of 18–29 years, which is in accordance with previous studies.[1]

ACD was the most common type of eczema in all the age groups. In the 18–29 years of age group, forefoot eczema followed by discoid eczema and juvenile plantar dermatosis, were other common types. LSC and discoid type in 30–49 years of age group and hyperkeratotic and asteatotic type in 50–65 years of age group. Chougule and Thappa[2] in their study of patterns of lower leg and foot eczema in South India found that the most common eczema in patients of 16–30 years of age group was ACD (25.6%), followed by discoid eczema, LSC, and cumulative irritant contact dermatitis.

There was a male predominance in our study (64%), with male:female ratio of 1.78:1. This could be attributed to the increased incidence of occupational exposure to allergens and occlusive footwear. Varying results have been obtained in previous studies.[3],[4]

Office workers (50%), students (24%), and homemakers (16%) formed the major bulk of the patients with foot eczema in our study. Footwear dermatitis was also more common among the above occupations. In addition, forefoot eczema (25%) and Juvenile plantar dermatitis (25%) were mostly seen in students, cumulative irritant contact dermatitis (25%) exclusively in homemakers and discoid eczema (12%) in office workers.

Patch testing not only helps in identifying the antigen responsible for causing the foot eczema, it also identifies the hitherto unknown antigen, which the patient should avoid while wearing his/her footwear. The most common allergen in our study was Parthenium (8 cases, 13.8%), which in turn shows the dominance of this plant as an allergen in India. Men predominate over females (5:3), as they are exposed to this allergen outdoors.[1],[2] The allergen most likely gets trapped under the strap of the footwear, eventually causing ACD. The importance of this finding lies in the fact that Parthenium has been removed from many standard series, but our study re-emphasizes the role of this plant in ACD. The other common allergens included potassium dichromate, mercaptobenzothiazole, diphenylguanidine (10.3% each), and PPD and black rubber mix in (6.9%) each. Among medicaments, positivity with nitrofurazone was noted in two patients and neomycin in one patient. The reduced numbers may be due to the fact that these medicaments are being used sparingly, due to their sensitizing potential.

In addition, potassium dichromate and mercaptobenzothiazole showed the highest male:female ratio of 5:1, probably as the occupational exposure and more preference of rubber footwear by males in India. Furthermore, chrome-free leather is less commonly used in India, due to its nonavailability and high cost. Hence, in India, allergens used in leather footwear are more commonly responsible for footwear dermatitis, when compared to the western world, where rubber is the more common allergen.[5] PPD showed the highest female:male ratio of 3:1, probably due to inadvertent use of dyes by women in the present era.

Our study showed that PPD (33.3%) was the most common allergen in homemakers, Parthenium (28.6%) in farmers, mercaptobenzothiazole (22.2%) in students, diphenyl guanidine (16.1%) followed by potassium dichromate (12.9%) in office workers.

Patch test positivity in our study was 60%, other studies showed positivity ranging from 60 to 88%.[1]

Various allergens have been identified in previous studies, and they vary from place to place.[4],[5] Mercaptobenzothiazole (36%), followed by colophony, 4-phenylenediamine base (20%), potassium dichromate, formaldehyde, nickel sulfate, black rubber mix, and thiuram mix were common allergens noted in one study, while among topical medications, neomycin (4%) gentamycin (12%) were frequently seen.[5]

Summary of the different studies done in India including the one done by us, showing various parameters, is shown in [Table 5].
Table 5: Comparison between our study and other studies from India

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It was found in our study that in patients with a clinical diagnosis of ACD, 63.2% (12/19) showed patch test positivity to 1 or more antigens, whereas in patients with a clinical diagnosis of foot eczema other than ACD, 58% (18/31) showed patch test positivity. It was indeed in the latter group, where patch test proved to be valuable in making the final diagnosis. In our study, patch testing had a reasonably high sensitivity of 58.1% and specificity of 36.8%. Hence, in patients with suspected footwear dermatitis, patch testing with both footwear series and Indian standard series should be done.

Summary

  1. Young and middle-aged adults (18–50 years) were more commonly affected with foot eczema
  2. Both foot eczema and footwear dermatitis had male preponderance
  3. Office workers formed the major bulk of foot eczema patients in our study
  4. ACD was the most common type of foot eczema
  5. Detergents, socks, plants were among the common aggravating factors for foot eczema
  6. The most common initial site of the presentation was dorsum of foot
  7. The most common allergen identified in our study was Parthenium, followed by potassium dichromate, mercaptobenzothiazole, and diphenylguanidine
  8. Correlation between clinical diagnosis of ACD and patch test results was seen in 63.2% patients
  9. Patch testing, with a sensitivity of 58.1% and specificity of 36.8%, maybe used as valuable, safe additional tool to aid the clinician's diagnosis and treatment of allergic contact dermatitis.



  Conclusion Top


The study reinforces the importance of patch test as a valuable tool in the diagnosis of foot eczema and should be done in every patient with ACD, with both Indian standard and Indian footwear series, the results of which are quite often surprising. Furthermore, Parthenium as a contact allergen is implicated not only in airborne contact dermatitis but also plays an important role in foot eczema.

Financial support and sponsorship

This study was supported by the Department of Dermatology, St. John's Medical College and Hospital, Bengaluru, Karnataka, India.

Conflicts of interest

There are no conflicts of interest.[7]



 
  References Top

1.
Priya KS, Kamath G, Martis J, D S, Shetty NJ, Bhat RM, et al. Foot eczema: The role of patch test in determining the causative agent using standard series. Indian J Dermatol 2008;53:68-9.  Back to cited text no. 1
[PUBMED]  [Full text]  
2.
Chougule A, Thappa DM. Patterns of lower leg and foot eczema in South India. Indian J Dermatol Venereol Leprol 2008;74:458-61.  Back to cited text no. 2
[PUBMED]  [Full text]  
3.
Narendra G, Srinivas CR. Patch testing with Indian standard series. Indian J Dermatol Venereol Leprol 2002;68:281-2.  Back to cited text no. 3
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4.
Sharma VK, Sethuraman G, Garg T, Verma KK, Ramam M. Patch testing with the Indian standard series in New Delhi. Contact Dermatitis 2004;51:319-21.  Back to cited text no. 4
    
5.
Bajaj AK, Saraswat A, Mukhija G, Rastogi S, Yadav S. Patch testing experience with 1000 patients. Indian J Dermatol Venereol Leprol 2007;73:313-8.  Back to cited text no. 5
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Garg T, Agarwal S, Rana S, Chander R. Patch testing in patients with suspected footwear dermatitis: A Retrospective study. Indian Dermatol Online J 2017;8:323-7.  Back to cited text no. 6
[PUBMED]  [Full text]  
7.
Chowdhuri S, Ghosh S. Epidemio-allergological study in 155 cases of footwear dermatitis. Indian J Dermatol Venereol Leprol 2007;73:319-22.  Back to cited text no. 7
[PUBMED]  [Full text]  


    Figures

  [Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5], [Figure 6], [Figure 7]
 
 
    Tables

  [Table 1], [Table 2], [Table 3], [Table 4], [Table 5]



 

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