684 JOURNAL OF TIlE SOCIETY OF COSMETIC CHEMISTS by patch testing and the healing of their rash on discontinuing to wear nail polish. In contrast to the clinical findings in these patients, Rein and Rogin (8), from the United States, have reported 47 patients who developed discoloration, separation and the accumulation of debris under the nail plates after using a base coat. This base coat contained a phenol formalde- hyde resin of the 32 patients tested to it 27 were found to be positive. They thought the resin actually penetrated the nail plate rather than the nail bed being contaminated during manicuring. A similar picture of inflammation of the nail bed, due to a base coat, has been reported by Reisch {0). In this instance the patient was not sensitive to the lacquer nor to its ingredients. An allergic reaction to hair dye is rarely missed by either patient or the physician. This allergy is widely known, by both the public and their doctors and is not so commonly seen by the dermatologist. 23 patients have been investigated in the past six years. It is likely that this number does not reflect the true incidence of the condition as many patients are probably diagnosed and treated by their own general practitioners, without reference to hospital. An allergic reaction to hair dye may begin within hours and is usually fully established within one or two days. The reaction tends to be acute and severe, with weeping of the scalp, redness and swelling of the face. The eyelids become puffy and swollen and the eyes may be completely closed, so that the patient is temporarily blinded. Patch testing should be deferred until the dermatitis is healed. This is necessary to avoid (a) a false positive reaction due to the irritable state of the skin in the acute stage, and (b) a false negative result, because in the acute phase the patient may temporarily be unable to react to the allergen and also to avoid a flare of the dermatitis secondary to a severe reaction at a patch test site. When recovered, the patient is tested to p-phenylenediamine 0.5%, p-toluylene diamine 1%, and o-nitro-p-phenylenediamine 2%. This is one of the few types of cosmetic dermatitis that afflicts men as well as women of the 23 patients referred to above, three were men, of whom two were either Indian or Pakistani. A most unusual reaction to hair bleach was described by Calnan and Shuster {10). A few patients were seen who, immediately after the applica- tion of bleach to hair, developed tingling of the scalp, redness and swelling of the face and in a severe reaction lost consciousness. Similarly, a hair- dresser described irritation of her scalp or hands after contact with bleach. The reaction was found to be caused by ammonium persulphate. A satura- ted solution of ammonium persulphate applied to intact or scratched skin

CONTACT DERMATITIS FROM COSMETICS 685 caused the development of an urticarial wheal. The wheal took minutes to develop and could not be elicited in skin depleted of histamine. 57 normal controls were tested and of these, four developed small wheals, and three developed large wheals. In the patients investigated, no definite conclusion was reached as to whether the reaction was an allergic immediate type antigen-antibody reaction or whether it was a direct release of histamine in a susceptible individual. Perfumes may cause allergic contact dermatitis. The reaction may be due to a perfume used as such or as an ingredient in an other cosmetic. Perfumes are alcoholic solutions and must therefore be diluted to 2% in olive oil for patch testing. A positive open test, in which the pure perfume is applied directly to the skin, is good confirmatory evidence of sensitivity. Identifying the allergen is difficult or completely impossible because of the complex nature of one perfume. It sometimes happens that after the application of a perfume and subsequent exposure to sunlight, brown pigmentation develops at the sites where perfume was present on the skin. This is known as berloque dermatitis (berlocke=pendant) because of the patterning of the pigmentation, which may resemble a hanging drop - particularly on the neck, where the perfume has trickled from behind the ear. The mechanism is not allergic but a photosensitivity due to the presence of phototoxic chemicals, probably psoralens, in the perfume. It is a difficult reaction to reproduce but Haber (11) succeeded by applying the perfume under polythene, thus enhancing its absorption. Subsequent exposure to sunlight, directly and through window glass, caused the develop- ment of erythema. Face creams and foundation creams cause little trouble, only eight patients having been diagnosed as being allergic to a preparation of this type. In five the allergen was traced. In three it was lanolin, in one the perfume, and in the fifth beeswax in a cold cream. Lanolin dermatitis, although uncommon, does occur (12), and all patients suspected of having cosmetic dermatitis are noxv routinely tested with 30% wool alcohols in Vaseline. This high concentration is used because sensitivity to lanolin is difficult to detect by patch testing the reason for this may be that the allergen is poorly absorbed or that it is present in minute amounts or because it is a weak antigem Patients with cosmetic dermatitis due to lanolin in a cream preparation are positive on patch testing to the cream itself, and to :30% wool alcohols in so[t paraffin. The presence of lanolin in the cosmetic can be confirmed from the manufacturers, and the patient is given a list of cosmetics not containing lanolin, which may be used safely.