SOME DIFFICULTIES OF TOPICAL TREATMENT IN DERMATOLOGY 41 A dry skin itches very commonly because of the minor inflammations or from sweat obstruction which gives a prickling sensation. Many people notice that they start prickling all over when getting into bed. This is quite common in active eczema or in abnormal dry skins. Bacteria breaking down protein will cause itchiness, but minor itching is a universal symptom which may easily be produced by a variety of causative mechanisms. As to treatment, we deal with most of the dry skins by trying to replace the water content with emollient ointments. Conditions like cracked hands or brittle nails can do very well with polythene gloves and a hydrous ointment. Such gloves may, however, lead to a sweat obstruction syndrome with prickly heat or a dyshidrotic eczema. The more severe degrees of ichthyosis are difficult to manage and we would really like some help in providing a satisfactory preparation which would be con- tinuously emollient and keep the patients comfortable. Anti-itching agents are mainly designed to cool the skin- cooling being an effective way of reducing irritation- to lessen the dryness or to have an antibacterial effect on organisms that degrade proteins into polypeptides causing itchiness. Many of these antibacterials and the anti- pruritics which act on the sensory system are, however, sensitizing agents. Abnormal skins often recover completely to their original, slightly abnormal state after slight irritations, but if the skin is sufficiently damaged it seems to develop the "bad habit" of producing the eruption again and again. In this category falls the individual who becomes more and more sensitized to the topical applications applied for the treatment of a skin condition. If the areas of imperfectly keratinized skin are removed in psoriasis, the skin almost returns to normal although it can never be completely normal. If areas of psoriasis are left untreated, there is a tendency to produce further psoriasis the longer the patient has it, the more chronic it becomes and the skin is more liable to develop the habit of producing it. The anti-inflammatory steroids first introduced for the treatment of psoriasis proved extremely effective, but as they became more potent, they began to cause trouble. We had already found that giving steroids internally to patients would suppress the psoriasis, but as soon as one withdrew the steroid, the psoriasis rebounded and was then more difficult to control. This is also a real difficulty with topical steroids sometimes the skin becomes so unstable that it produces psoriasis as a result of almost any stimulus and the psoriatic reaction may change qualitatively. The topical steroids are easily absorbed and they can produce quite marked collagen degeneration locally with thinning of the skin. The whole skin becomes more transparent, with the venules and capillaries showing through. Not only may there be a local degeneration but absorption and systemic degeneration may follow elsewhere giving rise to striae, for example, either at the site of application or in a remote site. Acne is a condition representing just a physiological variation in the normal skin. I feel that many of the present day treatments are not very satisfactory. Bacterial infection probably plays a major part in producing the gross scarring and inflam- matory lesions, but basically the problem is one of cleaning the skin and of removing the sebum and keratin plugging the sebaceous orifices. This is illustrated by cutting oil folliculitis, also known as "oil acne," due to contact with an engineers' cutting oil which results in obstruction of the hair follicles. These people require help by providing them with a cleansing agent which will emulsify the collection of petroleum oil and sebum in the pilosebaceous orifices. A very large percentage of workers on multiple cutting machines may be afflicted.

42 JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS While it is normal for every one to become pigmented, individual responses vary. Excessive pigmentation may represent photosensitivity due to certain perfume con- stituents, as in the case of bergamot oil. Hyperpigmentation is often difficult to diagnose and also to treat, since we are not certain of the causative agent to be avoided. In my experience, the treatment of melanotic pigmentation is unsatis- factory at the moment even when using hydroquinone benzyl ether. Equally difficult is the treatment of depigmented skin the process of demelanization is not yet unravelled, nor can we effectively disguise this. Some cases of vitiligo, an idiopathic absence of pigmentation in localized areas of skin, do recover spontane- ously, but other are permanent. The treatment with dihydroxyacetone is not, in my view, very helpful as it is most difficult to obtain the right shade of colour. The patient needs something to paint on his skin, perhaps daily, which he can adjust to his own colouring the shades given by dihydroxyacetone do not really approximate closely to natural skin. DISCUSSION MR. I. STEAD: In view of the comments in page 35 on antibiotics and hydroxy- quinoline derivates, do you suggest that quaternary ammonium salts are the most suitable agents for application to the skin ? If this is so, could you give me grounds to substantiate this ? THE LECTURER: In the early days there were a number of difficulties from agents included in these quaternary ammonium salts which gave rise to sensitivity. I think this has now been largely overcome. I also think that these agents may produce an irritant effect in areas of skin which are closely together. They are certainly less sensitizing than the antibiotics. MR. V. C. I-I. ]BROCKWELL: Surgical scrubs based on hexachlorophene are widely used in ]British hospitals. A report (12) suggested that such items based on an anionic sulphonate emulsifier giving a neutral pH were less prone to cause irritation than products employing solid soaps. Do you have any information concerning the use of surgical scrubs in the treatment of ache infections ? Would you like to com- ment on the adaptation and extension of such formulations for use as shaving creams ? Secondly, is it possible that photosensitization may be due to the combination of phenolic antibacterials with emulsifiers which necessitate a high pI-I ? THE LECTURER: I strongly support what you say about surgical scrubs incor- porating hexachlorophene. We use these for treatment of acne and patients find them helpful for cleaning. There are some people who find excessive use of soap somewhat harsh to the skin, and this anionic detergent is extremely well tolerated. Untoward effects are extremely rare, but I have seen a case where a lady presented a most extraordinary appearance after using one of these agents. Just along the hair margin she had a linear area of hyperkeratosis. It looked like excessive dandruff stuck onto the skin, and was certainly the result of treatment on stopping, it receded. It has been shown that some of these anionic detergents do have a hyper- plastic effect on the sebaceous gland. It did not react elsewhere. One has the impression, however, that some other people seem to complain of a little excessive (12) Brit. Med. y. 1 1254 (1963).