Background: Purpuric lesions have been described as an uncommon manifestation of allergic contact dermatitis in individual case reports.
Objective: We describe a series of patients who developed purpuric allergic contact dermatitis to textile dyes and resins in their personal clothing. Our purpose was to study the patients clinically and histopathologically and to define the most frequent allergens, which cause purpuric allergic contact dermatitis.
Methods: One hundred and three patients were clinically evaluated and tested with the Textile Color & Finish Series (TCFS) (Chemotechnique Diagnostics) and Standard Series (TRUE Tests) because of suspected allergic contact dermatitis (ACD) to clothing. The patients with clinical features of purpura as presenting sign of ACD were studied. Biopsies from the purpuric lesions were performed in three patients.
Results: Thirty of the 103 patients (29.1%) had positive reaction to an allergen from the TCFS. Clinically purpuric ACD was observed in 8.7% of all the cases studied (n = 9 of 103). Nine of the 30 patch-positive patients to the TCFS (30%) demonstrated purpuric macules, papules and patches. Patch testing of the nine patients with purpuric contact dermatitis, with the TCFS, resulted in 26 positive patch test results. The major causative allergens were the following: Disperse Blue 106 and Disperse Blue 124 in 26.9% each, Disperse Blue 85 in 11.5%, and ethyleneurea melamine formaldehyde in 7.7%. Positive patch tests were observed to dimethylol dihydroxyethyleneurea, dimethylol propyleneurea, tetramethylol acetylenediurea, urea formaldehyde, melamine formaldehyde, Disperse Red 17, and Basic Red 46 3.8% in each. Purpuric patch test reaction was observed in five cases. The patch test results had present relevance in all the cases. Lesional biopsies demonstrated acanthosis, spongiosis and parakeratosis. The blood vessels were dilated, without signs of vasculitis. The inflammatory infiltrate was composed of lymphocytes and erythrocytes. The extravasated erythrocytes had a perivascular and interstitial distribution in the superficial and deep plexus and were observed at the dermo-epidermal junction as well as in the epidermis.
Conclusion: Purpuric contact dermatitis is not an uncommon clinical form of ACD to textile dyes and resins. New allergens, which can evoke the development of purpuric allergic contact dermatitis and have not been described in the literature until now include: ethyleneurea melamineformaldehyde, dimethylol dihydroxyethyleneurea, tetramethylol acetylenediurea, urea formaldehyde, melamine formaldehyde and Disperse Red 17.