PRINCIPLES OF TREATMENT

Only those aspects of treatment which differ from routine practice or are related specifically to dermatology are described.

GENERAL

Washing-Routine washing with soap and water may do much harm or much good, depending on the particular disorder being treated. specific instructions must, therefore be given in every case. In eczematoug and exudative eruptions as a whole washing should be reduced to a minimum. Soap and water also usually aggravates seborrhoeic dermatitis, rosacea, and. pityriasis rosea. on the other hand frequent washing forms an integral part of the treatment of acne vulgarif and daily tar baths are prescribed for psoriasis. In all other conditions no changes need be made.

Diet- Dietetic treatment is tittle used in dermatology' occasionally some food, substance may be the cause of urti-caria and must therefore be eliminated. on the other hand, food and. drink play no part in either infantile eczemlu or any other eczematous Lruption. It is traditional to restrict the intake of carbohydrates in seborrhoeic dermatitis and chocolate in acne vulgaris, though usually little discernible improvement results. Any food or drink which normally tends to cause flushing, such as hot tea, spiced food or alcohol, will temporarily aggravate rosacea, but has no permanent effect. A reducing diet is probabty the most, useful dietetic weapon as many dermatological patients are over-weight and this materiaily aggravates their maladies. Finally a particular type of low fat diet may be used in the treatment of xantha- matosis

DRUGS-Systemic treatment is playing a larger and larger part in dermatology. specific drugs used in the treatment of individual diseases are described in the section dealing with those diseases. The following remarks concern the particular use in dermatology of drugs common to the whole of medicine.

Antipruritics- There is, unfortunately, no drug which has a specific effect on itching. some decrease of this symptom can hover be obtained by the judicious use of sedatives and antihistamines.

 Sedatives-These are extensively used to reduce tension, to relieve itching and to obtain sleep. Small doses, such as phenobarbitone, mg. 16 to 30 (gr.1/4  to 1/2) or amytal mg. 50 (gr. 3/4), may be given two or three times through the day and larger doses may be given at night. If itching is severe, very large  doses at night often only decrease the patient's ability to refrain from scratching, without inducing sleep. Tranquillisers have on the whole proved disappointing, although .hlotoptomazine (Largactil) and chlordiaziepoxide (Librium) are sometimes helpful, as are some of the newer phenothiazine derivatives.

Antihistamines do not prevent the liberation of histamine but, as the name indicates, inhibit its action. They also have a mild antipruritic effect which is quite separate from their antihistaminic action and which therefore can be utilised in other conditions. The different, compounds in this group vary in their length of action and in the intensity of their sedative effect. chlorpheniramine maleate (Piriton), cyproheptadine hydrochloride (Periactin) and triprolidine hydrochloride (Actidil) for instance are effective for about 4 hours and have a moderate sedative effect, which tends, as is the case with all members of this group of drugs, to become less marked the longer the substance is given. on the other hand, promethazine (Phenergan) exerts its effect for about 12 hours and, because it also has a marked. hypnotic effect, is best given last thing at night. The majority of these compounds are also available in the form of an elixir for the treatment of children and as injections for intramuscular or intravenous use. There are a great number of antihistamine drugs available and new ones are constantly being produced. Efrorts are now being concentrated on their antipruritic properties and trimeprazine, which is given in doses of l0 mg. three or four times a day, is one of the first marketed for this purpose. It has a definite, though unfortunately only slight, effect on itching. None of these substances have any antihistaminic effects when apptied locally, although they are markedly antipruritic when used in this way. Nevertheless, they should never be employed topically because of their sensitizing properties and the consequent risk of causing dermatitis.

Antibiotics

Bacterial. systemic antibiotics are less frequently required in dermatology than in other branches of medicine,since it is possible to control most, infections by local applications. when systemic therapy is necessary, penicillin remains the first choice, since the staphylococcus is by far the commonest infecting organism, being present in pure culture in over 60% of all infective conditions and in mixed culture in over 90%. The increasing number of resistant strains must however be borne in mind and these occur in about staphylococci, cloxacillin, areg enerally effective and it is rarely necessary to use chloramphenicol or any of the erythromycin group. The long-term use of penicillin in recurrent erysipelas and tetracycline in acnev ulgaris is dealt with in the sections dealing with those diseases. In choosing a loeal antibiotic three things must be borne in mind, the sensitivity of the organism, the potency of the antibiotic and its irritant effect on the skin. Thus penicillin and streptomycin are never used locally, since they so frequently cause a  sensitisationre action. Bacitracin and tyrothrycin are relatively weak antibiotics and of little use when used alone. The tetracyclines and erythromycins should not be used topically unless they are specifically indicated since, becauset hey are needed to combat serious systemic infections, every effort must be made to avoid increasing resistant strains of organism by unrlecessary use. This does not apply nearly so forcibly to chloramphenicol, but here the chanceso f causing a sensitisation dermatitis are greater than with the latter groups of antibiotics, but much less than with penicillin or streptomycin. The antibiotics of choice for external use are those which are never used systemically, namely neomycin, soframycin and polymyxin. The first two are available as ointments or lotions and control the great majority of infective conditions. If they fail and adequate bacteriological investigation is unavailable  a change should be made to chloramphenicol, especially as it is effective against most of the gram-negative organisms. Polymyxin, although very effective against staphylococci, should be exclusively reservedf or the treatment of infections due to pseudomonas pyocyanea. It is available as an ointment (Polyfax) and as a lotion (Otosporin).

Fungal. Nystatin, an artibiotie isolated from a strepto-myces, has a specific action against caniliila albieans (monilia). It may be prescribed in the form of an ointment, suspension, or ear drops (dissolved in propylene glycol), in a strength of 100,000international units per gram or millilitre, and as tablets (500,000 units per tablet) for oral use. The latter are not absorbed and only exert, their effects against candida in the gut. Amphoterecin B, obtained from streptomyces nodosus, is also effective against candida. It is used either locally or as a slow intravenous injection for systemic cases.