Contact leukoderma following irritant contact dermatitis to an isopropanol-based hand rub: A consequence of rigorous hand hygiene.

Contact leukoderma is usually due to direct melanocyte damage by aliphatic or aromatic phenols and catechols. Rarely, it can follow irritant or allergic contact dermatitis. The use of alcohol‐based hand rubs (ABHRs) has become prevalent in the general population since the start of the COVID‐19 pandemic. While ABHRs are usually well‐tolerated, they may incite irritant contact dermatitis (ICD) in conjunction with other irritants such as detergents and frequent hand washing. Continued use may result in permanent sequelae, such as contact leukoderma, as in our case, which has important consequences on skin of colour.

CASE REPORT

A 40‐year‐old male office worker presented with confluent depigmentation and a few confetti macules on the interdigital web spaces of both hands which had appeared one week ago (Figure 1). No other anatomical sites were involved. He had been regularly using a 70% (v/v) isopropanol (2‐propanol, CAS no. 67‐63‐0) hand rub for 2 months during the COVID‐19 pandemic. He had noticed itching and mild erythema over the web spaces after a few days of using the hand rub, but continued its application. He also reported frequent handwashing, sometimes with hot water, and doing wet household work without the application of moisturizers. No other potential irritants or allergens could be discerned from the history.

FIGURE 1

Clinical photograph showing confluent depigmentation with few confetti macules (black arrows) on all interdigital web spaces of (A) the right and (B) left hands. Fine scaling can be seen in the web spaces as well

A semi‐open test was performed (isopropanol being a potential irritant) with the undiluted sanitizer “as is” and in 50% dilution and a closed test was done with isopropanol 10% aq. along with the Indian baseline series. The tests were read as per International Contact Dermatitis Research Group grading at day (D)2 and D4 (Table S1). The semi‐open test with the sanitizer “as is” showed strong erythema and vesicles sharply limited to the site of application on D2, which rapidly resolved by D4, while the 10% aq. solution gave a negative result, favouring the diagnosis of an irritant reaction to the hand rub (Figure S1). A skin biopsy from the depigmented skin confirmed the absence of melanocytes on S‐100 immunohistochemical staining. In view of the confluent and confetti macules conforming to the site of exposure, he was diagnosed with contact leukoderma and advised to stop use of the hand rub and apply emollients, along with daily application of fluticasone and tacrolimus on the depigmented macules and the patch test site.2 The patch test site had not developed depigmentation at 8 weeks’ follow‐up and, while the depigmented macules did not increase, neither did they re‐pigment during that time.

DISCUSSION

Contact leukoderma following repeated use of certain chemicals, most frequently phenolic/catecholic derivatives, is a consequence of selective destruction of melanocytes, pigment transfer block, or decreased melanogenesis. Rarely, some chemicals may incite irritant or allergic contact dermatitis in certain at‐risk individuals resulting in pigment loss. Ghosh and Mukhopadhyay reported the largest study of 864 patients with chemical leukoderma in which only 5% had evidence of contact dermatitis at the site of depigmentation. Most cases followed topical exposures, presumably to higher concentration of the offending chemical delivered to cutaneous melanocytes.

Hand dermatitis is often an occupational dermatosis for healthcare workers and is more frequently irritant rather than allergic contact dermatitis. ABHRs are recommended for hand hygiene among healthcare workers but, since the the COVID‐19 pandemic, are now widely used also by the general population. Although subjective irritation is common, alcohol is not a strong irritant, and cases of irritant or allergic dermatitis are rare. However, multiple irritants used concurrently have a synergistic effect due to the alteration of skin permeability that would not occurr with one agent alone (the “crossover phenomenon”).8, 9, 10 Anionic detergents and repeated contact with water, especially hot water, are known irritants and probably augmented the propensity of isopropanol to cause ICD in the interdigital spaces in our case and contact leukoderma mirrored the distribution. The presence of confetti macules, earlier thought to be characteristic of chemical‐leukoderma, is now considered to be a sign of highly active vitiligo, but may signify rapid progression in contact leukoderma.

Contact leukoderma following ICD is very rarely reported; however, this could also be due to the difficulty in diagnosing ICD. A type of test (open/semi‐open/closed) and the concentration and vehicle which could be used while testing patients' products would be immensely helpful in diagnosing such cases. Irritant patch test reactions that resolve by D3/D4 can perhaps be used as guides to the diagnosis of ICD by patch testing in the absence of other tests.

Our case illustrates the problem of a typical occupational disorder which, owing to the uncontrolled use of sanitizers by the general public, led to the complication of contact leukoderma. The visible colour contrast, chronicity of the disease, and lack of uniformly effective treatment add to the psychological distress and stigma attached to leukoderma in individuals with skin of colour. Our case should serve as an example to restrict the unbridled use of such agents.

CONFLICT OF INTEREST

The authors declare no conflicts of interest.

AUTHOR CONTRIBUTIONS

Surabha Sinha: Conceptualization; data curation; formal analysis; writing‐original draft; writing‐review and editing. kabir sardana: Conceptualization; writing‐original draft; writing‐review and editing.

Table S1 Reading of semi‐open and closed patch tests.

Click here for additional data file.

Figure S1 The results on day 2 of the semi‐open test showing erythema and vesiculation limited to the site of application of the sanitizer “as is” and erythema over the site of application of the sanitizer in 50% dilution.

Click here for additional data file.