Photo‐Allergic Contact Dermatitis from Halogenated Phenolic Compounds1

Summary The clinical patterns of photo‐allergic contact dermatitis from several halogenated phenolic compounds which have been recorded in England, United States of America and Australia are described and discussed. Both transient and persistent light reactions have been seen in each country. The variability of clinical presentation resulted from the different ways in which the photo‐allergens were applied, either in soaps or in local medicinal preparations such as antiseptic or antifungal creams. Both the reactivity of each photo‐allergen and the availability of ultra‐violet light to cause it to react are important. The different clinical patterns which should arouse suspicion of photo‐allergic contact dermatitis are listed. It is suggested that these variable clinical pictures are essentially the result of the same biochemical mechanism and that photo‐allergic dermatitis, whether it occurs at the area of contact or at a distance, is the result of changes at the shin site in conjunction with immunological changes and not as the result of immunological changes akin to autosensitization.