More recently, sudan I in brilliant lake red was found to be a major impurity and potent sensitizer. These studies suggest that melanosis may be feature of contact dermatitis. Pigmentation cleared 6 months after use of the face powder was ceased. It was possible, however, that the pigmentation could have resulted from a phototoxic reaction to the lemon oil. These cases, particularly from Japan, clearly imply contact allergy to cosmetics resulting in pigmentary facial dermatosis, and, hence, Japanese authors have proposed the name pigmented cosmetic dermatitis.
Similarities do exist between pigmented cosmetic dermatitis and pigmented contact dermatitis.
Both result from exposure to small amounts of contact allergens and eczematous lesions are not seen in either. However, differences occur in causative agents between race and sex. In Japanese studies, fragrance compounds are implicated much frequently. Melasma is one of the main differential diagnoses. It has a typical spectacle shaped configuration.