Introduction

Hand dermatitis is a debilitating skin condition with a significant impact on morbidity and the capacity to perform activities of routine daily living and work. It is characterized in acute forms as erythema, scale/crust, erosions, vesicles, and bullae with variable edema and in chronic forms as persistent redness, scaling, lichenification, fissures, and erosions (see Fig. 1). In both settings, variably intense pruritus can be present. Occupational hand dermatitis, by its nomenclature, is caused, provoked, or exacerbated by exposures in the workplace setting. The disease is often multifactorial with more than one type of dermatitis occurring at the same time and may depend on the presence of pre-existing dermatoses or disorders of skin barrier function. Identifying the specific dermatosis and distinguishing individual contributors to the hand dermatitis, although often challenging, is important to deploy appropriate avoidance protocols and operational countermeasures, as well as a foundational therapeutic plan. The goal of this review is to critically examine literature over the past 3 years on occupational hand dermatitis and relate it to our current understanding of the disease and clinical practice. Note, while this review provides background on the topic, it does not aim to be a comprehensive overview.

Fig. 1
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Allergic contact dermatitis on the hand to multiple fragrances

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Occupational hand dermatitis includes irritant contact dermatitis (ICD) and allergic contact dermatitis (ACD) manifesting on the hands and caused by workplace exposures. ICD occurs due to direct cytotoxic effect of an adverse chemical or physical assault on the viable cellular components and non-viable barrier constituents of the skin. These events trigger activation of the innate immune response and proinflammatory signaling cascades with resultant dermatitis [1••]. ACD is caused by allergen-specific T cell activation and represents a type IV delayed-type hypersensitivity reaction. ACD begins with a sensitization phase, during which a low-molecular-weight hapten binds to an epidermal protein and triggers the innate immune response and activation of skin dendritic cells. These dendritic cells engulf the hapten-self protein complex, migrate to the draining lymph node, and present the complex to T cells, thus priming them against the allergen. Allergen-specific T cells then proliferate with the development of effector and memory subsets. Upon re-exposure to the allergen, a robust inflammatory response manifested as dermatitis occurs (also known as the elicitation phase) [1••].

Contact urticaria (CU) and protein contact dermatitis (PCD) are less common causes of hand skin disease that can be elicited by workplace exposures. CU manifests as pruritic wheals that appear within 60 min of exposure and resolve within 24 h. CU is a type I immediate-type hypersensitivity reaction and can occur through an IgE-mediated reaction to an allergen, which requires previous sensitization (immunologic CU), or through substance-triggered direct mast cell activation and histamine release (non-immunologic CU) [1••]. PCD typically begins as a pruritic wheal soon after skin-allergen contact and then progresses to an eczematous dermatitis. The pathophysiology of PCD is poorly understood but thought to have components of type I and IV hypersensitivity reaction and is often caused by high-molecular-weight proteins (in contrast to ACD) [1••].

Epidemiology

Occupational hand dermatitis is common. The most recent data released by the US Bureau of Labor Statistics showed the incidence rate of occupational skin diseases in 2020 was 1.8 per 10,000 full-time equivalent workers per year, second only to respiratory diseases among nonfatal occupational illnesses [2]. According to the Center for Disease Control (CDC), 90–95% of occupational skin diseases are contact dermatitis [3]. Up to 80% of cases of occupational contact dermatitis involve the hands [4], and thus occupational hand dermatitis represents a significant burden of all occupational disease. ICD is more common than ACD, but the specific distribution depends on geographic location [4]. CU and PCD are much less common.

In the UK, the EPIDERM surveillance system tracks reported cases of occupational dermatitis by dermatologists and occupational physicians [5]. Interestingly, review of the past 20 years of EPIDERM data shows a steady decline in reported number of occupational contact dermatitis cases [6]. The authors of the 2021 EPIDERM report note this may be due to “reporting fatigue” or tendency of physicians to report fewer cases over time; however, when adjusting for this phenomenon, the authors nevertheless suggest a downward trend in all occupational skin diseases between 1996 and 2019. The authors speculate the falling incidence may be due to decreased use of powdered latex gloves and reduced exposure to chromates in cement following the introduction of European legislation in 2005. At the same time, the authors note an increase in ACD caused by acrylates among beauticians [6].

Risk Factors

Skin barrier dysfunction, such as atopic dermatitis, increases the risk of development of contact dermatitis. This dysfunction not only facilitates cutaneous penetration of irritants and allergens, but also promotes a local inflammatory milieu conducive to the development of dermatitis. A systematic review and meta-analysis examined the risk-modifying effect of atopic dermatitis on hand dermatitis with a sub-analysis on occupational hand dermatitis. The risk of occupational hand dermatitis did, indeed, increase by approximately threefold in persons with atopic dermatitis compared to those without the disease (1-year odds ratio 4.31; 95% CI 2.08–8.91 and lifetime prevalence odds ratio 2.81; 95% CI 2.08–3.79) [7]. In light of these results, practitioners should consider counseling atopic patients on best practices to reduce hand dermatitis in the workplace.

Exogenous factors, such as wet work, have also been shown to increase risk of occupational hand dermatitis [8]. Using a cross-sectional questionnaire in the Netherlands, a recent study reaffirmed the association of wet work with occupational hand dermatitis but found that description of job tasks rather than job title provided a more accurate representation of risk of hand dermatitis. In particular, contact with fluids, use of gloves, and high frequency of hand washing represented high risk occupational wet work exposures [9]. Notably, the authors also found that non-occupational wet exposures, such as frequent hand washing outside of work, also contributed to risk of hand dermatitis [9]. Thus, when evaluating patients with potential occupational hand dermatitis, exposures outside of the work setting, such as recreational and domestic activities, must also be considered.

Diagnosis

Occupational hand dermatitis is associated, by definition, by exposure at work. Identifying a culprit and determining a specific connection between a patient’s presentation and an exposure can be challenging. The Mathias criteria were first outlined in 1989 and continue to provide a reliable and rigorous framework for establishing occupational causation [10]. The Mathias criteria consist of seven questions (see Table 1). Answering “yes” to four or more of the questions yields a 50% or greater probability of an occupational cause [10].

Table 1 Mathias criteria for establishing occupational causation of contact dermatitis
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Patch testing remains the gold standard for diagnosing ACD and is useful in identifying potential culprit allergens causing occupational hand dermatitis. Patch testing is a 4-to-5-day procedure. Test allergens are placed under occlusion in synthetic chambers (termed patch) on the back for 2 days. Patches are removed at 48 h, and the skin is assessed for an irritant reaction. The skin is then re-evaluated around 24 to 120 h later to assess for an allergic reaction. Negative results should not immediately eliminate the diagnosis of ACD; clinicians may contemplate the breadth, vehicle, and concentrations of the chemicals in the allergen battery, relatedness of the allergen series to the patient’s occupational exposures, any intrinsic or nosocomial immunosuppression, or the possibility of a newly emergent or not previously recognized allergen. Also, ICD can be clinically similar and may not provoke a positive patch test despite a disease relatedness to an occupational chemical or physical assault. At the same time, an analysis of the European Surveillance System on Contact Allergies showed that among patients ultimately diagnosed with ICD, patch testing still may yield positive results [12]. Careful consideration must be given to whether allergens are relevant to the patient when performing patch testing.

Common Occupational Allergens

Several allergens as assessed by patch testing are commonly implicated in occupational hand dermatitis:

Methylisothiazolinone

Methylisothiazolinone (MI) caused a contact allergy epidemic in the 2010s, peaking at 20% of patch-tested patients testing positive in some countries to this allergen in 2013–2014 [13–15]. Since then, European regulatory bodies moved to remove MI from leave-on cosmetic products, while in the USA, measures have been taken to reduce the concentration and thus the risk of sensitization and elicitation [16]. A careful analysis of the epidemiology of MI contact allergy shows an overall decline in patients testing positive to MI; however, when evaluating specific occupations, the authors find that the prevalence of MI contact allergy has continued to rise in some occupations, including painters [14]. Indeed, high concentrations of MI continued to be used in paints [17]. When evaluating a patient with hand dermatitis with positive patch test to MI, paint as well as personal care products may represent important exposure sources.

Nickel

Nickel is the most common allergen detected by patch testing in North America with a positivity rate of 17.5% among patch-tested patients [18]. Despite the ubiquity of this contact allergen, few studies have been published on the role of nickel in occupational skin disease. A recent study examined this question and found the rates of occupationally related nickel allergy were stable over time and most commonly affected the hands [19]. A wide variety of occupations were associated with nickel allergy including hairdressers, cosmetologists, machine workers, and healthcare workers. The most common sources of nickel were phones, machinery, tools, and work wearables (such as glasses, badges, and clips) [19]. The use of the dimethylglyoxime test (nickel spot test) may provide benefit in identifying potential clandestine sources of nickel in the workplace.

Fragrances

Fragrances are the second to third most common family of allergens to cause ACD (depending on the specific population evaluated) [18, 20]. One study found when testing for specific fragrances, citral, and hexyl cinnamal were more likely to be associated with an occupational exposure. Citral allergy was also more common in patients with hand eczema [21]. Unfortunately, data was not provided on the specific occupations that accounted for this association. The authors note that citral provides a citrus aroma and is commonly found in household products.

Rubber

Carbamates and thiurams are commonly used vulcanization accelerators and often implicated in rubber glove allergies [22]. Thiurams and dithiocarbamates are chemically closely related, representing a redox pair, and therefore thought to cross-react [22]. However, larger studies within European populations evaluating this cross-reactivity have yielded mix results [23]. Such studies in North American populations were lacking. A recent analysis filled this gap and found over 40% of individuals with positivity to one allergen were positive to the other [24]. The researchers went on to find that carba mix and thiuram mix allergies were commonly associated with occupation and, in particular, with exposure to personal protective equipment such as gloves, which is consistent with prior literature [22]. Interestingly, the researchers found an overall decrease in the prevalence of contact allergies to carba and thiuram mix from 1996 to 2001 in North America with stabilization of the prevalence of disease up until the end of the study period in 2016. The authors attribute this decrease to changes in manufacturing practices in the last 20 years [25, 26].

Healthcare Workers

Healthcare workers have an increased prevalence of occupational contact dermatitis compared to the general population [27, 28]. This difference is primarily due to the wet work required of healthcare workers including hand sanitation and glove-wearing. More frequent and diligent hand sanitation procedures were encouraged and implemented during the recent COVID-19 pandemic leading to a rise in occupational hand dermatitis in this population [29–31]. The rate of reported hand dermatitis symptoms was over 90% in one study suggesting an immense burden of disease among the healthcare worker population [30].

A UK and Ireland-based study found the majority of healthcare workers with occupational skin disease suffered from ICD (59%) due to frequent hand washing [29]. Workers with frequent direct patient contact, namely nurses and healthcare assistants, were most at risk. Importantly, the authors note that over 15% of patients presenting for an occupational dermatosis required time off work due to their skin disease [29]. This finding highlights the morbidity of occupational hand dermatitis and its potential to have a large impact not only on the individual, but also on workplace productivity, absenteeism, and presenteeism.

ACD also plays an important role in healthcare worker occupational skin disease. One case report described a healthcare worker with ACD to tetrahydroxypropyl ethylenediamine, which is found in hand sanitizer gels and is a chelator [32]. A larger retrospective study of patch-tested patients found that benzalkonium chloride positivity was associated with occupational exposure in healthcare workers likely due to hand sanitizer [33]. These studies highlight the importance of considering hand sanitizer as a cause of ACD.

Gloves also represent a significant source of ACD. In a study by Hamnerius et al., rubber additives were the most common cause of contact allergy in healthcare workers [34]. However, diagnosing glove-related ACD may be challenging: Santarossa et al. demonstrate that there is a discrepancy between standard patch testing, expanded-series rubber additive patch testing, and direct testing of pieces of gloves [35]. They attribute this difference to the low sensitivity of patch tests and/or to the presence of new additives in the gloves. Based on their findings, the authors call for more precise labeling of glove contents [35]. Goodier et al. sought to address this specific problem by contacting surgical glove manufacturers to compile lists of rubber additives present in each glove [36••]. Carbamates were the most common accelerator constituent, present in 90.5% of gloves. Their detailed study provides a useful resource on glove ingredients and aids with the identification of brands that are safe for patients with ACD to surgical gloves [36••] (see Tables 2 and 3).

Table 2 Medical exam gloves free of accelerators as advertised by the manufacturer*,a
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Table 3 Surgical gloves free of accelerators as advertised by the manufacturer*a
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Although rare, healthcare workers are at risk of develo** ACD to antibiotics due to frequent exposure. One case series reports on 4 nurses who had eczematous eruptions, all involving the hands, and were positive on patch testing to antibiotics [37]. All 4 nurses worked in the surgical department and frequently handled antibiotic solutions, sometimes with spillage on ungloved hands. Three nurses improved with avoidance of the culprit antibiotic [37].

Given the high burden of occupational hand dermatitis among healthcare workers, multiple efforts have been made to attenuate this disease in this population [38–41]. Unfortunately, attempts thus far have either had only short-term efficacy or been ineffective altogether. The Hand Eczema Trial was a randomized observer-blinded controlled trial initiated in 2009 in a population of healthcare workers with hand eczema. The intervention group received a consultation with a dermatologist who provided education on previously diagnosed allergen avoidance and general skin-protective behaviors. The control group received no interventions. Five months post-intervention, the intervention group had a significantly reduced Hand Eczema Severity Index (HECSI) scores compared to the control [42]. Graversgaard and colleagues wanted to probe the long-term effects of this intervention and sent a follow-up questionnaire to the participants 4 years after the initial intervention asking them about their self-reported eczema severity, quality of life, and knowledge of hand eczema prevention [41]. Unfortunately, the authors found no differences between the intervention and control groups suggesting the effects of the original study were short-lived [41]. Another group utilized a different strategy and conducted a trial wherein healthcare workers were randomized to wards with or without emollient cream dispensers [39]. The primary outcome of absolute change in HECSI score from baseline was not significantly different among the two groups [39]. The intervention group did apply cream significantly more often than the control, but at rates lower than recommended (measured 0.4 cream applications per shift, while 2 cream applications per shift were recommended) perhaps explaining the lack of observed effect [39]. Madan et al. attempted to combine the previous two interventions in a large randomized controlled trial involving 2040 nurses wherein the intervention group received access to a behavioral change program in addition to moisturizing creams [38]. Again, no differences were observed between the intervention and control groups. Brans comments on Madan’s study and states that face-to-face interventions, as in the original Hand Eczema Trial, may be necessary to have an effect [43]. Graversgaard’s work [41] suggests that such face-to-face instruction must be repeated over time to have a long-term effect.

Hairdressers

Hairdressers are at high risk of occupational hand dermatitis due to frequent wet work and exposure to numerous allergens and irritants including hair dyes, bleaching and perming products, shampoo, conditioners, and other hair cosmetics. A recent literature review shows that hairdressers are exposed up to 78 times more frequently to cosmetic products than ordinary consumers [44]. Hand dermatitis among hairdressers is common with a life-time prevalence of 38.2% (95% CI 32.6–43.8). The calculated incidence was 51.8 cases/1000 person years (95% CI 42.6–61.0) [45].

A recent study examined the long-term impact of hand dermatitis using data from a Danish prospective cohort study of hairdressers graduating from 1985 to 2007 [46, 47]. The authors found that hand dermatitis began early in one’s career, during apprenticeship. Risk factors include history of previous positive patch test, history of atopic dermatitis, and female sex [47]. Two-thirds of hairdressers reported in a 2009–2010 follow-up questionnaire that their hand dermatitis had resolved; however, one-third reported severe, persistent symptoms [47]. Hairdressers with persistent symptoms were more likely to leave the trade early [46]. Interestingly, the authors went on to find that leaving the trade was almost two times higher in hairdressers with a positive patch test to hair dye than to other allergens, perhaps due to inability to avoid hair dye compared to other allergens [46].

Two recent studies probed potential preventative measures for occupational hand dermatitis in this population. One study found that up to 18% of hairdresser apprentices have evidence of hand dermatitis on clinical examination at the start of vocational school [48]. They suggest that educational interventions may be helpful in this high-risk group. Another study took a different approach, by utilizing a chemically modified version of p-phenylenediamine (PPD) [49]. PPD with an added methoxymethyl side chain (ME-PPD) has a significantly lower sensitization potency in a local lymph node assay as compared to the original PPD molecule [50]. Studies investigating cross-reactivity of ME-PPD with PPD through open-use test found 30–48% of PPD-allergic individuals reacted to ME-PPD [51, 52]. Of subjects with a history of PPD-allergy and negative open use test to ME-PPD, 76% tolerated multiple ME-PPD-containing hair color treatments over the course of 1 year without symptoms [53]. Similar studies investigating whether hairdressers with occupational ACD to PPD are tolerant of ME-PPD have not been conducted. A recent study on typical hairdresser occupational exposure to ME-PPD found levels were below predicted concentrations for sensitization [50]. The authors suggest ME-PPD represents a potential alternative to PPD-containing dyes for avoidance of the development of occupational ACD.

Metalworkers

Metalworkers also represent a high-risk population for occupational hand dermatitis due to their exposure to wet work and a variety of contact allergens including metals, oils, greases and rubbers, and preservatives in cutting oils. Data for this group is scant, but the Information Network of Departments of Dermatology (a German, Swiss, and Austrian consortium on the clinical epidemiology of contact allergy) found that of patch-tested metalworkers, near 90% had hand dermatitis [54]. The spectrum of culprit allergens among metalworkers remains largely unchanged compared to prior research. Compared to a control group, metalworkers were more likely to be allergic to MI, formaldehyde, monoethanolamine, iodopropynyl butylcarbamate, and colophonium. Cutting metalworkers demonstrated particularly high rates of allergy with 12.6% testing positive to monoethanolamine (common ingredient in metal working fluids) and 11.4% testing positive to colophonium (used in adhesives and varnishes).

Several studies have investigated hand dermatitis prevention programs for metalworkers. In a study comparing metalworkers who participated in an educational intervention versus a control group, the authors found a significant decrease in hand eczema in the intervention group [55]. The intervention included multiple in-person training sessions and provision of skin care products [55]. In a separate study, the authors investigated the utility of secondary and tertiary individual prevention programs for metalworkers. Patients in the secondary prevention program participated in an educational seminar on skin protection and saw a dermatologist for two visits. Patients in the tertiary prevention program were admitted as inpatients for 3 weeks for intensive management followed by a 3-week outpatient program with a dermatologist. The authors found both programs improve hand eczema severity scores [56]. Patients in the secondary prevention program had lower disease scores at the end of the study than the patients in the tertiary prevention program; however, the patients in the tertiary prevention program experienced a larger decrease in severity score over time. These studies show that preventative programs can be helpful; however, intensive resources are required. Despite these costs, an analysis showed that the tertiary prevention program with inpatient admission was cost-effective in the German healthcare system, when considering the cost of re-training individuals who leave their profession [57]. Such programs may be feasible where governments take on the cost of retraining but may not be scalable to countries that do not sponsor trade education.

Other Occupations

Several recent studies report on allergen trends within other specific occupations with high prevalence of hand dermatitis. Perhaps not surprisingly, propolis was found to be a common allergen among beekeepers with nearly 30% of patch-tested beekeepers testing positive for this allergen [58]. Painters were found to be more likely to test positive to epoxy resin and MI compared to the general population [59]. As noted previously, MI is found in high concentrations in paints (see “Methylisothiazolinone” section). Dental personnel were found to have increased rates of glutaraldehyde, thiuram mix and carba mix allergy likely due to exposure to gloves, dental materials, and sterilizing solutions [60]. Acrylates also remain a common allergen among dentists due to exposure to acrylic compounds used in dental prostheses [60]. Veterinarians and veterinary assistant staff were found to have high rates of occupational hand dermatitis due to wet work. This population also had an increased rate of contact urticaria, attributed to their contact with fur-bearing animals [61].

Contact Urticaria and Protein Contact Dermatitis

CU has frequently been observed in occupational settings and commonly involves the hands. A large variety of agents have been reported to cause CU including animal and plant products, fragrances, cosmetics, preservatives, medications, and metals [62]. CU can manifest with systemic symptoms, and therefore a careful review of symptoms, including pulmonary and gastrointestinal, is important when evaluating patients with this disease.

PCD is rare; however, when observed, this disease is often triggered by occupational exposure and present on the hands. The four classic groups of proteins known to cause PCD are fruits/vegetables/spices/plants, animal proteins, grains, and enzymes [63]. Reflective of these groups, the occupations most likely to suffer from PCD are food and animal handlers. Prick and scratch tests are the most sensitive for this condition as patch tests often yield a negative result, likely due to inability of large proteins to penetrate the intact skin barrier [64].

In a Finnish study, 10% of patients with occupational skin disease were diagnosed with CU and/or PCD (the authors were unable to distinguish between the two diseases given the registry data) [65]. Most cases were due to animal-derived materials, followed by plant products, and chemicals. Farm workers were most at risk for CU/PCD followed by food-workers such as cooks, bakers, and food machine operators [66]. A separate study found that almost half the patients presenting with occupational CU or PCD have concomitant occupational airway disease [67]. Therefore, it is important to screen patients presenting for CU or PCD for pulmonary symptoms.

A German study investigating the epidemiology of CU found that it is commonly caused by an occupational trigger [68]. The distribution of occupations in the Germany study was different from the Finnish with healthcare workers being most represented, possibly due to the study’s focus on CU without PCD and the different study population. Common CU triggers included gloves, disinfectants, and rubber (other than gloves) [68]. A separate study found the self-reported rate of CU was up to 8.2% in a survey of healthcare workers [69] suggesting this may be a high-risk population for CU.

Multiple recent case reports describe novel occupational CU triggers including diethyl phthalate in hand sanitizers among healthcare workers [70], indigo dye in natural hair dyes among hairdressers [71], pork among slaughterhouse workers [72], buckwheat among food handlers [73], and legume pests among farmers [74].

A recent French study focusing on occupational contact dermatitis caused by artichokes observed 2 cases due to PCD [75]. The hands were involved in both cases. One study subject worked packing frozen vegetables. The other was a farmer of artichokes and chrysanthemums. This study highlights artichokes as a newly reported etiology of occupational PCD.

Prognosis

Occupational hand dermatitis can have a significant impact on one’s quality of life and persistence of symptoms is more likely to lead to career change [46]. Multiple factors affect the prognosis of occupational hand dermatitis [76]. Interestingly, a recent study found that while history of atopic dermatitis and positive patch tests may be risk factors for the development of disease, these are not factors that predict disease persistence. Rather lifestyle factors were found to influence prognosis. Greater than 4 h of exercise a week was positively associated with clearance of disease, while smoking and stress were negatively associated with disease clearance in a multivariate analysis [76]. Change of profession was also associated with remission. Thus, counseling on lifestyle factors and sensible hygiene and protective or avoidance practices may be important in clearing occupational hand dermatitis.

The importance of addressing persistent symptoms is further supported by Passlov’s recent study on how hand dermatitis impacts patients’ quality of life [77]. The authors find that hand eczema causes measurable impairment of hand strength and dexterity with consequent impairment of ability to perform activities of daily living. The authors go on to show improvement in these measures with improvement of hand dermatitis severity [77].

Interventions

Skin protective behaviors are critical in preventing and managing occupational hand dermatitis. A recent study showed a dose–response relationship between decreasing wet work and improvement of hand dermatitis suggesting that limiting wet work may lead to hand dermatitis clearance [78]. A Cochrane review on preventing occupational irritant hand dermatitis concluded that evidence was insufficient to confidently assess effectiveness of interventions but did note that moisturizers with or without barrier creams may result in a protective effect [79].

If avoidance of an allergen or wet work within a profession is not possible, some patients may choose to leave their profession. Multiple studies have shown that change in profession does result in improvement in occupational hand dermatitis [76, 78, 80•]. However, while eczema severity scores improve, Carøe et al. observed in their cohort of patients that job change had a concurrent negative effect on overall quality of life [80•]. Interestingly, the authors found that if work procedures rather than profession was changed, both eczema and overall quality of life scores improved [80•]. This finding highlights the importance of working with patients and employers to find ways for patients to remain at their current jobs if desired.

We discuss above hand dermatitis prevention programs within the context of specific occupations. Several studies have examined the utility of such programs in a broader context. PREVEX, a randomized controlled trial investigated the effect of a 2-h educational program on skin protective behavior compared to a control group [81]. Patients diagnosed in Denmark with an occupational skin disease were recruited. A follow-up questionnaire was administered 1 year later revealing that the intervention resulted in increased knowledge of skin-protective behaviors but decreased self-efficacy (or belief in one’s capacity to effect self-change) [81]. The authors conclude that the intervention was overall insufficient to have an impact on hand dermatitis. These results mirror studies previously discussed (see “Healthcare Workers” section) that showed brief educational programs had little impact on occupational hand dermatitis prevention. Only intensive educational programs (as discussed in the “Metalworkers” section) may be effective. A Cochrane review on interventions for preventing occupational irritant hand dermatitis found that there was insufficient evidence to assess effectiveness of educational programs [79].

Whenever possible, primary prevention, such as system and operational changes that serve to reduce human exposure to allergens and irritants is most preferable (e.g., closed versus open systems). Another strategy is to reduce the dependency on human hands as direct tools of trade. Secondary measures such as gloves that prevent allergen or irritant permeability to the skin and emollients to foster barrier integrity all serve to mitigate hand dermatitis caused by exogenous sources.

For patients in which changing roles to avoid occupational hand dermatitis triggers is not possible or is not fully effective, treatment options exist. Multiple case reports and series show the efficacy of dupilumab, an IL-4 receptor subunit inhibitor, in treating ICD and/or ACD [82–84]. Several of the reported cases include patients with hyperkeratotic hand dermatitis clearing with dupilumab despite continued occupational exposure [82, 83]. However, for others, dupilumab failed to improve occupational hand dermatitis due to ACD to a rubber additive [85]. Other therapeutics developed for atopic dermatitis and specifically hand eczema are on the horizon including systemic and topical Janus kinase inhibitors whose broader mechanisms of action may prove effective in the complex pathophysiology of occupational and non-occupational hand eczema. The evolution of treatment will depend, in part, to a greater understanding of the ambiguous pathophysiology of ACD to different allergens that likely transcend the dogmatic views of solely Th1 lymphocytes and their attendant cytokines [86–88].

Conclusions

The wealth of literature over the past 3 years on occupational hand dermatitis shows that occupational hand dermatitis is an enduring worldwide problem and is a large unmet medical issue. Scalable effective prevention programs remain elusive and wet work continues to contribute to an epidemic of ICD. System changes can influence reactivity to allergens and possible dermatitis. Future work should focus on effective and implementable occupational hand dermatitis prevention programs and on methods to mitigate the consequences of wet work. Continued research is also needed on the ever-evolving spectrum of allergens that cause occupational skin disease so as to best diagnose and manage occupationally caused ACD.