Brilliant Lake Red R as a cause of pigmented contact dermatitis

Twenty-three patients suffering from pigmented contact dermatitis caused by cosmetics containing Brilliant Lake Red R were observed. Commercial samples of Brilliant Lake Red R proved to contain many ethyl acetate extractable impurities; 1-phenylazo-2-naphthol and azobenzene were isolated and identified. To determine the responsible allergens, five patients were examined by patch tests with purified samples of azo-dyes and the unidentified fractions of ethyl acetate extractable impurities. Three out of five showed weaker reactions to purified samples of Brilliant Lake Red R and the other two showed equal reactions compared to the commercial product. 1-Phenylazo-2-naphthol was found to be a strong allergen in all cases but none showed a positive reaction to azobenzene. Some unidentified fractions also gave positive results. Patch tests were performed with 4-phenylazo-1-naphthol, 4-phenylazo-1-naphthol-2-carboxylic acid, and 2,4-bis(phenylazo)-1-naphthol, as structurally related compounds derived from 1-naphthol. All gave negative and they were not detected in the ethyl acetate extractable impurities by thin-layer chromatography.     

Occupational pigmented contact dermatitis from azo-dyes

A 51-year-old man had been working in a dye factory for 25 years and had noticed itching and pigmentation on the extremities for the past 5 years. Patch testing showed positive reactions to Sudan I and Vacanceine Red, among the azo dyes which he had been handling. After he changed his work, he became free from erythematous lesions with itching. The pigmentation almost disappeared 10 months later.     

Pigmented cosmetic dermatitis and coal tar dyes

Patch tests and photopatch tests with various cosmetics, coal tar dyes, perfumes, lanolin preparations and parabens-mix were performed in 53 patients with pigmented cosmetic dermatitis similar in clinical appearance to Riehl's melanosis. The results showed that coal tar dyes, particularly brilliant lake red R, were closely related to the cause of the disease. In patch testing and photopatch testing with coal tar dyes, the incidence of positive responses to the brilliant lake red R was found to be significantly higher than that to the other coal tar colors (22/38 = 57.9%). The relevance of ultraviolet light to the disease was found to be much less than the ratio expected (14/47 = 29.8%). A high incidence of positive responses to fragrances was also found, but it is considered to play a secondary role in the etiology of the disease.     

Pigmented contact dermatitis due to musk moskene.

Musk moskene is a soft, sweet fragrance resembling musk ambrette which introduces a very desirable creamy powder note for cosmetic fragrance. Because of its advantages, which include low cost, oil solubility, and less sensitive to sunlight, musk moskene has recently increased its share of the market. In this paper, we reported a case with pigmented contact dermatitis from musk moskene in cheek rouges. Patch test positive reactions to cheek rouges resulted in hyperpigmentation. Both the perfume used in the cheek rouges and musk moskene, which was a component of that perfume, showed strongly positive reactions. Residual hyperpigmentation was seen on the regions of the perfume and musk moskene patch testings. Hyperpigmentation on cheeks of the patient gradually diminished after discontinuing use of the causative cheek rouge.     

Pigmented contact dermatitis due to therapeutic sensitizer as complication of contact immunotherapy in alopecia areata

Pigmentary complication by contact immunotherapy (CI) for alopecia areata (AA) has been reported but its pathophysiology remains unknown. To characterize pigmentary complication by CI and its pathophysiology, we examined the incidence of hyperpigmentation in 186 consecutive patients treated with CI using diphenylcyclopropenone. From clinical data of AA totalis (AAT) or universalis (AAU) patients (n = 78), we studied the correlations between this complication and age, sex, atopic background, duration and treatment responsiveness, duration of CI, final concentration of diphenylcyclopropenone and administration of anti‐histamines by χ²‐test or Mann–Whitney U‐test. Additionally, the histopathology of pigmentation was studied. As a result, 11 (5.91%) of the 186 patients had hyperpigmentation in this series. All of them had AAT or AAU, suggesting that the pigmentation is apt to occur in severe AA. When the AAT or AAU patients with (n = 11) and without hyperpigmentation (n = 67) were compared, those with pigmentation showed poorer responsiveness to CI (P < 0.05) but no significant tendency for other factors. Histopathologically, skin specimens showed lichenoid or vacuolar interface dermatitis with necrotic keratinocytes and dermal melanophages, consistent with pigmented contact dermatitis (PCD). Together, pigmentary complication by CI corresponds to PCD from therapeutic sensitizer, representing clinical indicator of poor responsiveness.