THE doctor who treats diseases of the skin is at a disadvantage compared with his colleagues in other branches of medicine. He deals with an organ which can be seen and felt, and it is impossible to hoodwink a patient into thinking that the complaint has improved when obviously it has not. Many patients with skin disease believe that because the lesion is on the surface it should be easy to cure and any failure in treatment implies that his doctor is a fool. The patient who has spent a sleepless night because of an irritation is highly critical and even aggressive towards his doctor, and it is this feeling of blameworthiness in the doctor which increases his difficulties.
There is a great temptation to change treatment needlessly and start the great evil of dermatology, over-treatment. Few doctors, other than trained specialists, have confidence in their ability to diagnose and treat skin conditions and this lack of confidence is soon conveyed to the patient. Yet the diagnosis and management of the common skin dis-orders is not particularly difficult and allows the doctor to play detective more than many other branches of medicine.
The skin is part of the whole being and changes in it may reflect systemic or psychological disorders. Accurate observation of the skin may, therefore, assist in the diagnosis of general disease.
The foundation stone of the diagnosis is the history. Not only can the correct diagnosis be frequently deduced, from the history alone, but some assessment of the personality of the patient can be made. It is permissible to have a brief glance at the lesion of which the patient complains in order to save time. Obviously, if the patient has a wart on the hand or a rodent ulcer on the face, there is no point in taking a lengthy history, but for most skin eruptions, a comprehensive history before a full examination is advisable. The duration of disease, the first site affected and the mode of subsequent spread should be elicited. What has been applied by the patient? The majority try several remedies before consulting a doctor and are unwilling to admit this, yet the whole character of a skin eruption can be masked by a reaction to local applications. Are there symptoms from the rash? Does it itch or burn and if so, is it worse at any particular time? The itching of scabies is particularly noticeable at night whereas chronic urticaria is most severe on waking. Is there a previous history of skin disease? The same type as the present, or was it different? Are other members of the family affected? A positive answer suggests either contagious disease or a genetic disorder. Have other members of the family suffered from hay fever, asthma or urticaria? These diseases are known to be associated with chronic eczema. What is the patient’s occupation? It is not sufficient to discover that he is a turner, many skin conditions arise from contact with substances which slowly damage the skin and it is important to know exactly what has happened at work; as in the case of a turner, what metals are being turned? Is the lathe lubricated with soluble oil? How are the hands protected and cleaned? Has the patient hobbies which entail contact with skin irritants? If a man, does he help with the washing up or home decorating? What is the patient’s general health, has he been able to sleep, or has he been mentally irritable or depressed? Are medicines of any type being taken? Here it may be necessary to ask leading questions since patients do not remember aspirins, routine sleeping tablets and aperients. Finally, it is always worthwhile asking the patient for his or her theories for the cause of the complaint. Often these are erroneous, sometimes humorous, but a useful clue may be provided. It also gives a guide to the patient’s knowledge of medicine which will be helpful in later discussion of the complaint.
Having taken the history, a diagnosis may be suggested, certainly some will be excluded. For instance, if the eruption has been present ten years a self-limiting virus infection, lasting a few weeks, is an impossibility.
Except where the diagnosis is obvious and trivial, such as a simple wart, the patient must be undressed and examined completely, preferably in daylight since small degrees of colour variation are not easily seen in artificial light. A lens capable of magnification up to 5 times is essential. Complete examination should be insisted on since it is a frequent occurrence for a patient to deny that there are any lesions on the covered parts of the body and yet on complete examination an eruption is found. This is not always a result of deliberate deception. A mild dermatitis of the eyelids is often the first sign of a generalised allergic reaction from an area of gravitational dermatitis, yet the patient may not mention the leg condition because the association does not occur to him. A complete examination will reveal the leg eruption and provide the correct diagnosis. Another common association is between the hands and feet. Fungus infection of the toes causes an eruption on the hands, therefore no examination of a rash on the hands is satisfactory unless the feet are also examined. The scalp, the nails and the mucous membranes are all part of the skin and must be included in the examination. Any enlargement of superficial lymphatic glands should be noted. Always remember it is the whole patient that is being examined and take note of abnormalities in other organs than the skin.
The skin lesions
In order to discuss changes in the skin, it is necessary to have a standard descriptive terminology and when examining a rash an attempt should be made to find the earliest lesion and to define this. A macule is a localised change in colour of the skin with no elevation or infiltration, a common example is a freckle, but macules can be erythematous, purpuric or pigmented. A papule is a small solid elevation; papules can be flat topped or conical, round or polyhedral, follicular when related to hair follicles, smooth or scaly. A vesicle is a small collection of fluid either in the epidermis or between the epidermis and dermis. It may be difficult to determine whether an elevated lesion is a papule or a vesicle and in eczematous eruptions there is a transition from papule to vesicle.
A pustule is a superficial collection of pus in the skin and pustules may form as a result of purulent change in a vesicle or de novo. A bulla is a collection of fluid larger than a vesicle the roof of which may be the whole or part of the epidermis. A wheal is a transient elevation of the skin caused by oedema in the dermis and surrounding capillary dilatation.
Certain secondary changes may result from the primary lesions. Scales which are heaped up horny layer or dead epidermis may develop as a result of inflammatory changes. If serum, pus or blood dry on the skin crusts are formed. Fissures and cracks occur in skin folds and where inflamed thickened inelastic skin moves over joints. Superficial loss of skin or mucous membranes gives rise to erosions, deeper loss is described as ulceration. An aggregation of chronic inflammatory cells in the dermis, such as occurs in chronic infection with tuberculosis or leprosy, gives rise to a translucent papule usually of yellowish-brown hue. Such change is termed a granulomatous reaction and a very similar appearance is given by infiltration with neoplastic cells.
Having identified the type of lesion affecting the-skin, much can be learned from its distribution. This can best be assessed from a distance of 6 feet. On the whole, endogenous eruptions are symmetrical, affecting mirror image areas. Psoriasis affects the extensor aspects of the limbs whilst lichen planus more often involves the flexor surfaces. It may be that only those parts of the skin exposed to light are inflamed, in that case, the back of the hands, the face, the V of the neck, but not the area beneath the chin, will be affected. A few congenital abnormalities have a segmental distribution but the common unilateral segmental eruption is herpes zoster which appears on the skin supplied by one cutaneous nerve root. Purely linear lesions suggest plant sensitivity, artefact or the Koebner phenomenon, in which skin damage by a scratch may be the site of an endogenous eruption such as psoriasis or lichen planus. Certain diseases have unique features such as the burrow of scabies or the umbilicated nodule of molluscum contagiosum and when they are found the diagnosis is not in doubt.
Even with the most careful history and examination, a definite diagnosis may not be possible. There are many investigative procedures which can then assist and of these histological examination by light microscopy is still one of the most important. Information may be obtained about enzyme activity by special histochemical stains and im- munofluorescent examination will detect the presence of immunoglobulins and complement in the tissues. Occasionally electron- microscopy may be indicated. Bacteriological and mycological examination of pus, scales or hair and investigation of the patients’ blood or urine, may all be necessary. If allergic contact dermatitis is suspected patch tests will be required to confirm specific sensitivity.
Finally, observation over a period of time may provide the solution. The diagnosis of a lesion which on first appearance is atypical or misleading may, in its later stages, appear obvious. Patients with contact dermatitis often cannot, at the first interview, remember all the substances they have handled; at a subsequent interview the cause may be recalled with ease.
Having attained a diagnosis, the disease must be viewed against the background of the individual. There may be no problem if a patient has only a simple infection easily controlled by topical treatment but there are many factors to consider in, for instance, a housewife’s dermatitis. In this condition the skin of the hands becomes red, cracked and irritable owing to excessive contact with soap or detergents and water. There may be an hereditary weakness which will be shown by a history of skin disease in relatives. Previous attacks or an undue dryness of the skin of the rest of the body denote a constitutional liability. A recent difference in the degree of contact with soap and water may have occurred; perhaps the patient has just had a baby or has been widowed and has to do extra domestic work. The skin is more likely to break down if poorly nourished and thus anaemia or malnutrition may be factors. Skin damage appears more often during hormonal changes such as the menopause and in old age. It is probable that the general state of tissue irritability and the sweating mechanisms can also be altered by emotional tension. Emotional upsets certainly influence symptoms and the complaint will thus be aggravated by unhappiness, anxiety and depression. It can be seen, therefore, that what seems a relatively simple problem is the end result of many contributory factors. Housewives’ dermatitis has been taken as an example but similar factors are at work in many patients with skin disease. Many will recover with use of routine treatment but in order to achieve the best result an attempt should be made to correct as many other contributory factors as possible.
As mentioned before, the big danger in the management of skin diseases is over-treatment. This term means irritation of the skin by applications which in themselves are irritants, applied too frequently and cleaned off” too vigorously. From the treatment aspect skin eruptions can be classified into four main groups—
(1) Those which if protected from the doctor and the patient will recover.
(2) Those conditions which require skin rest by the application of inert and soothing preparations.
(3) Infections which need a specific antibiotic or fungicide.
(4) Those diseases which in the present state of our knowledge are uninfluenced by treatment.
When in doubt use the simplest and safest applications is the maxim to be kept constantly in mind.
Patients with skin disease are more disturbed by their complaint than patients with other medical disorders. Skin eruptions still produce the leper complex, a feeling of shame, disgust and fear and it is this emotional state which adds to the difficulty of the management of skin patients. Irritation, which is such a constant symptom of skin disease, disturbs sleep and is frequently more lowering to the morale than pain. Fear that the disease is contagious and will spread to relatives and friends adds to the patient’s misery.
If these fears are recognised by the doctor and discussed, even though they are not voiced by the patient, anxiety will be lessened and this can only be beneficial whatever the dermatosis. Fear is the motive which brings many patients for consultation and even though the skin complaint may be incurable the fact that the disease is recognised and its natural history is known relieves symptoms in a surprisingly high proportion of patients.