Local adverse reactions commonly occur after topical use.
Other side effects are uncommon but can include nausea and vomiting.
Causes The disease occurs in epidemics affecting especially children under the age of ten years. It is due to the varicella zoster virus, and the condition is an extremely infectious one from child to child. Although an attack confers life-long immunity, the virus may lie dormant and manifest itself in adult life as HERPES ZOSTER or shingles.
Symptoms There is an incubation period of 14–21 days after infection, and then the child becomes feverish or has a slight shivering, or may feel more severely ill with vomiting and pains in the back and legs. Almost at the same time, an eruption consisting of red pimples which quickly change into vesicles ?lled with clear ?uid appears on the back and chest, sometimes about the forehead, and less frequently on the limbs. These vesicles appear over several days and during the second day may show a change of their contents to turbid, purulent ?uid. Within a day or two they burst, or, at all events, shrivel up and become covered with brownish crusts. The small crusts have all dried up and fallen o? in little more than a week and recovery is almost always complete.
Treatment The fever can be reduced with paracetamol and the itching soothed with CALAMINE lotion. If the child has an immune disorder, is suffering from a major complication such as pneumonia, or is very unwell, an antiviral drug (aciclovir) can be used. It is likely to be e?ective only at an early stage. A vaccine is available in many parts of the world but is not used in the UK; the argument against its use is that it may delay chickenpox until adult life when the disease tends to be much more severe.... chickenpox
– there may be epidemics spread by the bite of mosquitoes or ticks.
The clinical features begin with in?uenza-like symptoms – aches, temperature and wretchedness; then the patient develops a headache with drowsiness, confusion and neck sti?ness. Severely ill patients develop changes in behaviour, abnormalities of speech, and deterioration, sometimes with epileptic seizures. Some develop paralysis and memory loss. CT (see COMPUTED TOMOGRAPHY) and MRI brain scans show brain swelling, and damage to the temporal lobes if the herpes virus is involved. ELECTROENCEPHALOGRAPHY (EEG), which records the brainwaves, is abnormal. Diagnosis is possible by an examination of the blood or other body ?uids for antibody reaction to the virus, and modern laboratory techniques are very speci?c.
In general, drugs are not e?ective against viruses – antibiotics are of no use. Herpes encephalitis does respond to treatment with the antiviral agent, aciclovir. Treatment is supportive: patients should be given painkillers, and ?uid replacement drugs to reduce brain swelling and counter epilepsy if it occurs. Fortunately, most sufferers from encephalitis make a complete recovery, but some are left severely disabled with physical defects, personality and memory disturbance, and epileptic ?ts. Rabies is always fatal and the changes found in patients with AIDS are almost always progressive. Except in very speci?c circumstances, it is not possible to be immunised against encephalitis.
Encephalitis lethargica is one, now rare, variety that reached epidemic levels after World War I. It was characterised by drowsiness and headache leading on to COMA. The disease occasionally occurs as a complication after mumps and sometimes affected individuals subsequently develop postencephalitic PARKINSONISM.... encephalitis
Symptoms Symptoms vary with the age of infection. In young infants, herpes simplex may cause a generalised infection which is sometimes fatal. In young children the infection is usually in the mouth, and this may be associated with enlargement of the glands in the neck, general irritability and fever. The condition usually settles in 7–10 days. In adults the vesicles may occur anywhere in the skin or mucous membranes: the more common sites are the lips, mouth and face, where they are known as cold sores. The vesicles may also appear on the genitalia (herpes genitalis) or in the conjunctiva or cornea of the EYE, and the brain may be infected, causing ENCEPHALITIS or MENINGITIS. The ?rst sign is the appearance of small painful swellings; these quickly develop into vesicles which contain clear ?uid and are surrounded by a reddened area of skin. Some people are particularly liable to recurrent attacks, and these often tend to be associated with some debilitating condition or infection, such as pneumonia.
Except in the case of herpes of the cornea, the eruption clears completely unless it becomes contaminated with some other organism. In the case of the cornea, there may be residual scarring, which may impair vision.
Treatment Aciclovir is e?ective both topically as cream or eye drops or orally. In severe systemic infections it can be given intravenously.... herpes simplex
Causes Shingles is due to the same virus that causes chickenpox. This invades the ganglia of the nerves, particularly the spinal nerves of the chest and the ?fth cranial nerve which supplies the face. Despite being due to the same virus as chickenpox, it is rare for herpes zoster to occur as a result of contact with a case of chickenpox. On the other hand, it is not unusual for a patient with herpes zoster to infect a child with chickenpox. It is a disease of adults rather than children, and the older the person, the more likely he or she is to develop the disease. Thus in adults under 50, the incidence is around 2·5 per 1,000 people a year; between 50 and 60 it is around 5 per 1,000; whilst in octogenarians it is 10 per 1,000. Occasionally it may be associated with some serious underlying disease such as LEUKAEMIA, LYMPHADENOMA, or multiple myeloma (see MYELOMATOSIS).
Symptoms The ?rst symptoms are much like those of any feverish attack. The person feels unwell for some days, has a slight rise of temperature, and feels vague pain in the side or in various other parts. Often the area of skin to be affected feels hypersensitive (hyperaesthesia) as though something were rubbing on it. The pain ?nally settles at a point in the side, and, two or three days after the ?rst symptoms, the rash appears. Minute yellow blebs – or vesicles, as they are known – are seen on the skin of the back, of the side, or of the front of the chest, or simultaneously on all three, the points corresponding to the space between one pair of ribs right around. These blebs increase in number for some days, and spread until there is often a complete half-girdle around one side of the chest. The pain in this stage is severe, but it appears to vary a good deal with age, being slight in children and very severe in old people, in whom indeed herpes sometimes forms a serious illness. After one or two weeks, most of the vesicles have dried up and formed scabs. The pain may not pass o? when the eruption disappears, but may remain for weeks or even months – a condition known as post-herpetic NEURALGIA. Old people are prone to develop this condition.
Treatment ACICLOVIR or famciclovir can be given orally, and are e?ective if started in large doses early in the attack. Later, topical antibiotics may be required. Analgesics may be necessary if neuralgia is severe.... herpes zoster
2. It is mostly acquired as a result of sexual activity; some cases are caused by simplex type
1. After initial infection the virus lies latent in the dorsal nerve root ganglion (of the spinal cord) which enervates the affected area of the skin. Latent virus is never cured and reactivation results in either a recurrence of symptoms or in asymptomatic shedding of the virus which then infects a sexual partner. Around 30,000 cases of genital herpes are reported annually from clinics dealing with SEXUALLY TRANSMITTED DISEASES (STDS) in England, but there are also many unrecognised (by either patient or doctor) infections. Patients may have a history of painful attacks of ulceration of the genitals for many years before seeking medical advice. All patients with a ?rst episode of the infection should be given oral antiviral treatment, and those who suffer more than six attacks a year should be considered for suppressive antiviral treatment. ACICLOVIR, valaciclovir and famciclovir are all e?ective antiviral drugs. If a woman in the ?nal three months of her pregnancy contracts herpes genitalis, this can have serious consequences for the baby as he or she will be at risk of herpes encephalitis after delivery.... herpes genitalis
There are three main categories of licensed medicinal product. Drugs in small quantities can, if they are perceived to be safe, be licensed for general sale (GSL – general sales list), and may then be sold in any retail shop. P (pharmacy-only) medicines can be sold from a registered pharmacy by or under the supervision of a pharmacist (see PHARMACISTS); no prescription is needed. P and GSL medicines are together known as OTCs – that is, ‘over-thecounter medicines’. POM (prescription-only medicines) can only be obtained from a registered pharmacy on the prescription of a doctor or dentist. As more information is gathered on the safety of drugs, and more emphasis put on individual responsibility for health, there is a trend towards allowing drugs that were once POM to be more widely available as P medicines. Examples include HYDROCORTISONE 1 per cent cream for skin rashes, CIMETIDINE for indigestion, and ACICLOVIR for cold sores. Care is needed to avoid taking a P medicine that might alter the actions of another medicine taken with it, or that might be unsuitable for other reasons. Patients should read the patient-information lea?et, and seek the pharmacist’s advice if they have any doubt about the information. They should tell their pharmacist or doctor if the medicine results in any unexpected effects.
Potentially dangerous drugs are preparations referred to under the Misuse of Drugs Act 1971 and subsequent regulations approved in 1985. Described as CONTROLLED DRUGS, these include such preparations as COCAINE, MORPHINE, DIAMORPHINE, LSD (see LYSERGIC ACID
DIETHYLAMIDE (LSD)), PETHIDINE HYDROCHLORIDE, AMPHETAMINES, BARBITURATES and most BENZODIAZEPINES.
Naming of drugs A European Community Directive (92/27/EEC) requires the use of the Recommended International Non-proprietary Name (rINN) for medicinal substances. For most of these the British Approved Name (BAN) and rINN were identical; where the two were di?erent, the BAN has been modi?ed in line with the rINN. Doctors and other authorised subscribers are advised to write titles of drugs and preparations in full because uno?cial abbreviations may be misinterpreted. Where a drug or preparation has a non-proprietary (generic) title, this should be used in prescribing unless there is a genuine problem over the bioavailability properties of a proprietary drug and its generic equivalent.
Where proprietary – commercially registered
– names exist, they may in general be used only for products supplied by the trademark owners. Countries outside the European Union have their own regulations for the naming of medicines.
Methods of administration The ways in which drugs are given are increasingly ingenious. Most are still given by mouth; some oral preparations (‘slow release’ or ‘controlled release’ preparations) are designed to release their contents slowly into the gut, to maintain the action of the drug.
Buccal preparations are allowed to dissolve in the mouth, and sublingual ones are dissolved under the tongue. The other end of the gastrointestinal tract can also absorb drugs: suppositories inserted in the rectum can be used for their local actions – for example, as laxatives – or to allow absorption when taking the drug by mouth is di?cult or impossible – for example, during a convulsion, or when vomiting.
Small amounts of drug can be absorbed through the intact skin, and for very potent drugs like OESTROGENS (female sex hormones) or the anti-anginal drug GLYCERYL TRINITRATE, a drug-releasing ‘patch’ can be used. Drugs can be inhaled into the lungs as a ?ne powder to treat or prevent ASTHMA attacks. They can also be dispersed (‘nebulised’) as a ?ne mist which can be administered with compressed air or oxygen. Spraying a drug into the nostril, so that it can be absorbed through the lining of the nose into the bloodstream, can avoid destruction of the drug in the stomach. This route is used for a small number of drugs like antidiuretic hormone (see VASOPRESSIN).
Injection remains an important route of administering drugs both locally (for example, into joints or into the eyeball), and into the bloodstream. For this latter purpose, drugs can be given under the skin – that is, subcutaneously (s.c. – also called hypodermic injection); into muscle – intramuscularly (i.m.); or into a vein – intravenously (i.v.). Oily or crystalline preparations of drugs injected subcutaneously form a ‘depot’ from which they are absorbed only slowly into the blood. The action of drugs such as TESTOSTERONE and INSULIN can be prolonged by using such preparations, which also allow contraceptive ‘implants’ that work for some months (see CONTRACEPTION).... medicines
In many cases, an outbreak of cold sores is preceded by tingling in the lips, followed by the formation of small blisters that enlarge, causing itching and soreness. Within a few days they burst and become encrusted. Most disappear within a week. The antiviral drug aciclovir in a cream may prevent cold sores if used at the first sign of tingling.... cold sore
Genital herpes cannot be cured, but treatment can reduce the severity of symptoms. Antiviral drugs such as aciclovir make the ulcers less painful and also encourage healing. Other measures include taking analgesic drugs and bathing with a salt solution.
Once the virus enters the body, it stays there for the rest of the person’s life. Recurrent attacks may occur, usually during periods when the person is feeling run down, anxious, or depressed, before menstruation, or after sexual intercourse. The virus can be spread to others through sexual intercourse even when symptoms are absent. Recurrent attacks tend to become less frequent and less severe over time.Genital herpes may be passed from a pregnant woman to her baby during delivery.
If the virus can be detected in vaginal swabs, delivery by caesarean section is usually recommended.... herpes, genital
Herpes zoster (shingles) is caused by the varicella-zoster virus, which also causes chickenpox. Following an attack of chickenpox, the virus lies dormant in the dorsal root ganglia of the spinal cord. Later, under one of a number of influences, the virus migrates down the sensory nerve to affect one or more *dermatomes on the skin in a band, causing the characteristic shingles rash. One side of the face or an eye (ophthalmic zoster) may be involved. Shingles may be chronically painful (post-herpetic neuralgia), especially in the elderly. See also Ramsay Hunt syndrome.
Treatment of all forms of herpes is with an appropriate preparation of *aciclovir or related antiviral drugs; shingles may require potent analgesics and treatment of secondary bacterial infection.... herpes
Bacterial meningitis is treated with antibiotics administered as soon as possible after diagnosis. With the exception of herpes simplex *encephalitis (which is treated with aciclovir), viral meningitis does not respond to drugs but normally has a relatively benign prognosis. See also leptomeningitis; pachymeningitis.... meningitis
Health Encyclopedia