Allergic contact dermatitis caused by a black tattoo ink in a patient allergic to shellac

Contact Allergy to Shellac. Retrospective Cross-Sectional Study With Data From the Spanish Registry of Research in Contact Dermatitis and Cutaneous Allergy (REIDAC)

INTRODUCTION

Shellac is a known allergen present mainly in cosmetics used on the eyelids and lips, although new sources of exposure have recently been described. Our objective was to assess the use of shellac as a contact allergen in Spain and the clinical profile of patients allergic to shellac.

METHODS

This retrospective cross-sectional study included patients patch tested for shellac between 2018 and 2021 from the Spanish Registry of Contact Dermatitis and Cutaneous Allergy (REIDAC).

RESULTS

A total of 980 patients were patch tested for shellac (20% in ethanol), and 37 (3.77%, 95% confidence interval [CI], 2.58-3.97%) showed positive results. Most of these patients were tested for shellac due to a suspicion of cosmetic contact dermatitis. Seven patients with present relevance were found, five with relation to cosmetics, and the other two with an occupational background of food handling. The reaction index for shellac was 0.51 and the positivity ratio was 67.56% (95% CI, 52.48-82.65%).

CONCLUSIONS

Shellac appears to be a prevalent allergen in patients with suspected contact dermatitis related with cosmetics or foodstuff. However, further studies are needed to validate its use in other patients.

Hypersensitivity to permanent tattoos: Literature summary and comprehensive review of patch tested tattoo patients 1997-2022

We outline constituents of tattoo and permanent make-up ink with regard to inflammatory tattoo reactions and population-based confounders. The comprehensive review of patch-tested tattoo patients between 1997 and 2022 shows that tattoo allergy cannot be reliably diagnosed via patch testing with today's knowledge. Weak penetration and slow haptenization of pigments, unavailability of pigments as test allergens and a lack of knowledge concerning relevant epitopes hamper the diagnosis of tattoo allergy. Patch testing p-phenylenediamine and disperse (textile) dyes is not able to close this gap. Sensitization to metals was associated with all types of tattoo complications, although often not clinically relevant for the tattoo reaction. Binders and industrial biocides are frequently missing on ink declarations and should be patch tested. The pigment carbon black (C.I. 77266) is no skin sensitizer. Patch tests with culprit inks were usually positive with cheap ink products for non-professional use or with professionally used inks in patients with eczematous reactions characterized by papules and infiltration. Tape stripping before patch testing and patch test readings on Day 8 or 10 may improve the diagnostic quality. The meaningfulness of the categorical EU-wide ban of Pigment Green 7 and Pigment Blue 15:3 is not substantiated by the presented data.

Tattoos - more than just colored skin? Searching for tattoo allergens

During tattooing, a high amount of ink is injected into the skin. Tattoo inks contain numerous substances such as the coloring pigments, impurities, solvents, emulsifiers, and preservatives. Black amorphous carbon particles (carbon black), white titanium dioxide, azo or polycyclic pigments create all varieties of color shades in the visible spectrum. Some ingredients of tattoo inks might be hazardous and allergenic chemicals of unknown potential. In Germany, about 20 % of the general population is tattooed and related adverse reactions are increasingly reported. Since tattoo needles inevitably harm the skin, microorganisms can enter the wound and may cause infections. Non-allergic inflammatory reactions (for example cutaneous granuloma and pseudolymphoma) as well as allergic reactions may emerge during or after wound healing. Especially with allergies occurring after weeks, months or years, it remains difficult to identify the specific ingredient(s) that trigger the reaction. This review summarizes possible adverse effects related to tattooing with a focus on the development of tattoo-mediated allergies. To date, relevant allergens were only identified in rare cases. Here we present established methods and discuss current experimental approaches to identify culprit allergens in tattoo inks - via testing of the patient and in vitro approaches.

Contact Allergy: A Review of Current Problems from a Clinical Perspective

Contact allergy is common, affecting 27% of the general population in Europe. Original publications, including case reports, published since 2016 (inclusive) were identified with the aim of collating a full review of current problems in the field. To this end, a literature search employing methods of systematic reviewing was performed in the Medline^® and Web of Science™ databases on 28 January 2018, using the search terms (“contact sensitization” or “contact allergy”). Of 446 non-duplicate publications identified by above search, 147 were excluded based on scrutiny of title, abstract and key words. Of the remaining 299 examined in full text, 291 were deemed appropriate for inclusion, and main findings were summarised in topic sections. In conclusion, diverse sources of exposures to chemicals of widely-differing types and structures, continue to induce sensitisation in man and may result in allergic contact dermatitis. Many of the chemicals are “evergreen” but others are “newcomers”. Vigilance and proper investigation (patch testing) are required to detect and inform of the presence of these haptens to which our populations remain exposed.