Cross‐elicitation responses to 2‐methoxymethyl‐p‐phenylenediamine in p‐phenylenediamine‐allergic individuals: Results from open use testing and diagnostic patch testing

Background

Allergic contact dermatitis caused by p‐phenylenediamine (PPD) is a health concern for hair dye users. Because of its lower sensitization potency, the PPD derivative 2‐methoxymethyl‐p‐phenylenediamine (ME‐PPD) has been developed as an alternative hair dye for primary prevention. However, cross‐elicitation responses can occur in PPD‐allergic subjects.

Objectives

To compare cross‐elicitation responses to ME‐PPD in open use and diagnostic patch testing of PPD‐allergic subjects with hair dye‐related allergic contact dermatitis.

Methods

Reactions to ME‐PPD were investigated in 25 PPD‐allergic subjects by performing (1) 45‐minute open use testing with a hair dye containing 2.0% of either ME‐PPD or PPD, and (2) patch testing with increasing ME‐PPD concentrations (0.1%–2.0% pet.).

Results

Of the 25 PPD‐allergic subjects, 21 (84%) reacted to open use testing with a hair dye containing 2.0% PPD, and testing with 2.0% ME‐PPD led to cross‐elicitation in 12 (48%). When patch tested with increasing ME‐PPD concentrations, 13 (52%) cross‐reacted at 0.1% (lowest dose) and 21 (84%) at 2.0% (highest dose), indicating decreased reactivity as compared with published PPD dose‐response data.

Conclusion

In line with the decreased cross‐reactivity of ME‐PPD in hair dye open use testing, PPD‐allergic subjects show an attenuated cross‐elicitation dose response to ME‐PPD in patch testing.     

Allergic contact dermatitis to substitute hair dyes in a patient allergic to para‐phenylenediamine: Pure henna,black tea and indigo powder

We report a case of a 50‐year‐old lady with allergic contact dermatitis to para‐phenylenediamine, who in her quest to find a substitute hair dye, subsequently reacted to a number of plant‐based hair dyes, including pure henna, black tea and indigo powder respectively. While these substances all contain tannins, testing to possible constituents tannic acid and gallic acid was negative.     

Late reactions to patch test preparations with reduced concentrations of p-phenylenediamine: a multicentre investigation of the German Contact Dermatitis Research Group

Background. p‐Phenylenediamine (PPD) 1% in petrolatum has been shown in a prospective study to elicit late reactions in 1.5% of routine patch tests, which may be indicative of patch test sensitization. Objectives. To assess the frequency of late reactions to reduced PPD patch test concentrations. Methods. In 1838 patients, PPD was tested at three concentrations (0.5% pet., group I; 0.4% pet., group II; and 0.35% pet., group III). Patch tests were read on D1 (D2) to D3 (D4); additional late readings were performed on D7, D14, and D21. Patients who were not able to return for all scheduled late readings were telephoned on D7, D14, and D21, and questioned about a reaction at the patch test sites. Results. Data of 1666 patients (1069 women and 597 men) were eligible. Late reactions were observed in 9 patients, 3 in group I (0.49%) and 5 in group II (0.63%). In 7 of 8 of the patients with late reactions, patch tests were applied for 48 hr. On retesting, 4 of 5 patients became positive at D2 or D3. Conclusions. The occurrence of late reactions to PPD may be influenced by patch test concentration and duration. PPD 0.4–0.5% pet. may cause late reactions indicative of active sensitization.     

Intolerance reactions to knee arthroplasty in patients with nickel/cobalt allergy and disappearance of symptoms after revision surgery with titanium‐based endoprostheses

Intolerance reactions to metal implants may present as dermatitis, impaired wound healing, effusions, pain or loosening. The clinical relevance of metal allergy in the differential diagnosis is often unclear and patients may even tolerate implants containing metals to which they are allergic. We present four patients with knee arthroplasty in whom after exclusion of infection or mechanical causes, a nickel/cobalt allergy led to replacement surgery with titanium‐based prostheses. The subsequent alleviation of symptoms underlined the relevance and usefulness of allergological diagnostics in selected cases of complicated arthroplasty.