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).

SOME DIFFICULTIES OF TOPICAL TREATMENT IN DERMATOLOGY 43 greasiness of their skin which may link with Skog's work that anionic detergents do have a hyperplastic effect upon sebaceous glands. I believe that hexachlorophene and the Parabens are already used as antibacterial agents in shaving creams. I should have thought that people who have the type of skin which easily gets infected, or that which does not stand up to over-washing, might well be helped by putting an anionic detergent into shaving cream. I am unable to answer your last question. DR. H. W. HIBBOTT: I would like to make two comments. As I was listening to you I felt that we had a refreshing change in the dermatologist's outlook towards cosmetics. Apart from a slight indictment of bergamot you have not come down heavily on cosmetics as a great cause of trouble for the medical profession, very contrary to some lectures we have listened to in this Society from dermatologists. I think this represents a change to which this Society has been looking forward for some years. Looking at some of your rather wonderful slides, even when we saw lips in very bad condition you did not blame it on lipsticks. In this case, too, I feel that lipsticks, apart from being quite glamorous, are in fact very good lip salves and women are a very lucky half of the population in being able to wear them. I was very impressed by your outlook towards the cosmetic industry, and I feel that we ourselves are showing that we are really thinking hard about possible adverse effects on the skin, and that the results we are getting are showing up to the medical profession. MR. 13. CHtMBERS: Can you suggest the main cause of itching which accompany acute cases of dandruff ? THE LECTURER: Dandruff comprises dead cells (dander) which are being exfoliated .and are being shed as a result of p•roteolytic enzymes. As a result you are bound to get some itching sensation as a normal state of affairs. Itching in the perianal region is very commonly due to bacterial breakdown of protein. Bacteria can grow very easilyin a greasy, sebaceous area, and once you have a combination of desquamated cells with sebum you have a medium in which organisms will grow, and itching results. I would have thought that head itching is very often related to staphylococcal or ,other infections. You can, however, get emotional itching of the head, which may be due to some alteration in tension in the erector pili muscle, the hair standing .on end through nervous sympathetic stimulus when you get anxious. People also go white due to nervous vagotonic influences. Thus a state of tension affecting the hair muscle will produce itching. It is very common for people to scratch their head -in order to get rid of their tension. MRs. H. BUTLER According to you, as I understand it, some irritation is caused by blocking of the sweat gland. Is it not also caused by changes of temperature ? know a man who only gets severe itching in frosty weather, leading to eczema when he gets in front of a hot fire. That is not necessarily blocking of the sweat glands, it ? THE LECTURER: This is another problem the vascular supply of the skin differs in many places and once the skin is damaged the vessels become unstable and will leak. The response to histamine is also different. If you burn your hand, the result of that burn may lead to an unstable bit of skin which will flush up easily for as