An unusual case of a combined severe type I immediate hypersensitivity reaction and delayed type IV allergic contact dermatitis caused by hair dyes including toluene-2,5-diamine in the same patient

We report the case of a 55-year-old male office worker, who developed extensive urticarial lesions starting on the scalp and face followed by abdominal cramps, nausea and vomiting less than 30 min after hair dye application. He immediately consulted the emergency department of our hospital where an extensive urticarial rash without respiratory or cardiovascular complications was documented. His condition rapidly improved upon treatment with prednisolone and antihistamines [Correction added on 7 August 2024, after first online publication: IV was deleted from the preceding sentence.].

The patient had a pre-existing diagnosis of chronic plaque psoriasis. He had no previous history of atopy, no previous immediate reactions to hair dyes and never had any temporary black henna tattoos done.

However, for more than 1 year, he had noticed itching of the scalp associated with eczematous lesions of the ears and forehead some days after dyeing his hair. As his symptoms were less severe, he did not feel the need to seek medical attention.

General consent was obtained from the patient. Skin tests were performed under strict medical monitoring. Standard patch tests with our baseline, cosmetic, and hairdressing series (supplied by Chemotechnique Diagnostics, Vellinge, Sweden) using IQ ultra patch test chambers (Chemotechnique Diagnostics) as well as semi-opened patch testing with the patients' personal dyes diluted with 10% aqua were applied. As rapidly as 20 min after epicutaneous application of American Crew—Precision Blend (AC) (American Crew, New-York, USA) and Wella-Koleston Perfect (Wella, Rothenkirchen, Germany) (W) dyes with and without adjunction of hydrogen peroxide the patient developed a localised papular reaction on the test site. There was no malaise or other systemic symptoms. Allergens were then applied for 48 h and readings performed on day (D) 2 and D4. Readings on D2 and D4 showed +++ positive reactions for p-phenylenediamine (PPD; 1% pet.) and toluene-2,5-diamine (PTD; 1% pet.), and ++ positive reactions to AC and W dyes.

Prick tests with the colour blend formula AC and W gave positive results (6 and 4 mm wheals, respectively) with appropriate positive and negative controls. We also performed prick test with PPD 1% pet., PTD 1% pet., m-aminophenol 1% pet., resorcinol 1% pet. A positive reaction at 20 min (7 mm wheal) was only seen with PTD.

Allergic contact dermatitis (ACD) to hair dyes is a frequent problem, both in consumers and hairdressers.¹ The two main culprits usually are PPD and PTD, but many other components of hair dyes are described as eliciting substances. In recent years, it has been shown that the use of PTD in commercial products in Europe was increasingly more frequent than PPD.² A few cases of anaphylactoid reactions to hair dyes with acute facial lesions mimicking angioedema occurring hours following dye application were also published.³ In contrast to common anaphylactic reactions, these reactions are usually not associated with systemic symptoms. True anaphylaxis to hair dyes have also been described; however, they seem to be rare.⁴ Unlike anaphylactoid reactions, they occur within minutes after application of the colour and are regularly associated with classical systemic signs of immediate allergy reactions. Different compounds have been shown to trigger such reactions (PPD, PTD, 4-methylaminophenol, 4-aminophenol, Basic blue 99, 2,4-diaminophenoxyethanol).⁵ In our case, prick tests were positive for PTD but negative for PPD. Both substances should have been also tested in aqua, as data report cases of false-negative reactions to PPD prick testing in pet.⁴

Up to date, the precise mechanism of anaphylaxis to hair dyes remains unclear and complex as many unstable and oxidated derivatives products arise following dyeing. In the case of severe contact urticaria with shock to PTD, an oxidation product of PTD, the so-called Bandrowski's base was presumed to be the eliciting substance.⁶ Recent in vitro studies also showed activation of mast cells via the key target MRGPRX2 in mice by PPD. The resulting release of tryptase might be a possible mechanism to explain those reactions.⁷ To our knowledge, so far only a few cases of combined immediate hypersensitivity and ACD induced by hair dyes were described.^{5, 8} In summary, the spectrum of hair dye reactions is broad, this case report should remind us that sometimes both ACD and immediate reactions can occur together. It is important for clinicians not to underestimate the latter, which can be severe and even lead to shock.

Aurélie Piletta-Zanin: Conceptualization; investigation; writing – original draft; methodology. Ophélie Marchal: Investigation. Damien Pastor: Investigation. Pierre Piletta-Zanin: Supervision; conceptualization. Thomas Harr: Writing – review and editing; supervision.

The authors declare no conflicts of interest.