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A common dichoto- mous result is x-ray results which are read as either normal or abnormal and showing a particular abnormality best 5mg ditropan gastritis symptoms in dogs. There is also the middle ground order ditropan on line amex gastritis recovery, or gray zone buy ditropan 2.5mg gastritis jugo de papa, in these tests as sometimes they will be unreadable because of poor technical quality. In addition, there are many subtle gradations that can appear on an x-ray and lead to various readings, but they may not pertain to the disease for which the patient is being evaluated. The serum sodium level or the level of other blood components is an example of a con- tinuous test. A patient can have any of a theoretically inﬁnite number of values for the test result. In real life, serum sodium can take any value from about 100 252 Essential Evidence-Based Medicine Fig. In practice, we often take continuous tests and select a set of values for the variable that will be con- sidered normal (135–145 mEq/dL for serum sodium) thereby turning this con- tinuous test into a dichotomous test, which is reported as normal or abnormal. Values of the serum sodium below 135 mEq/dL, called hyponatremia, or above 145 mEq/dL, called hypernatremia, are both abnormal. Deﬁnitions of a normal test result There are many mathematical ways to describe the results of a diagnostic test as normal or abnormal. In the method of percentiles, cutoffs are chosen at pre- set percentiles of the diagnostic test results. All values above the upper limit or below the lower limit of the normal percentiles are abnormal. Results are only speciﬁc to the population being studied and cannot be general- ized to other populations. One is for patients who are afﬂicted with the disease and the other is for those free of dis- ease. There is usually an overlap of the distributions of test values for the sick and not-sick populations. Some disease-free patients will have abnormal test results while some diseased patients will have normal results, thus setting any single value of the test as the cutoff between normal and abnormal will usually misclassify some patients. The ideal test, the gold standard, will have none of this overlap between diseased and non-diseased populations and will therefore be able to differentiate between them perfectly at all times. Ideally, when a research study of a diagnostic test is done, patients with and without the disease are all given both the diagnostic test and the gold-standard test. The results will show that some patients with a positive gold-standard test, and who have the disease, will have a positive diagnostic test and some will have a negative diagnostic test. The ones with a positive test are the true positives and those with a negative test are false negatives. A similar situation exists among patients who have a negative gold-standard test and therefore, are all actually disease-free. Some of them will have a negative diagnostic test result and are called true negatives and some will have a positive test result and are called false positives. Strength of a diagnostic test The results of a clinical study of a diagnostic test can determine the strength of the test. The ideal diagnostic test, the gold standard, will always discriminate dis- eased from non-diseased individuals in a population. The diagnostic test we are comparing to the gold standard is a test that is easier, cheaper, or safer than the gold standard, and we want to know its accuracy. That tells us how often it is correct, yielding either a true positive or true negative result and how often it is incorrect yielding either a false positive or false negative result. From the results of this type of study, we can create a 2 × 2 table that divides a real or hypothetical population into four groups depending on their disease 254 Essential Evidence-Based Medicine Fig. Patients are either diseased (D+) or free of disease (D–) as determined by the gold standard test. The diagnostic test is applied to the sample, and patients have either a positive (T+) or negative (T–) diagnostic test. We can then create a 2 × 2 table to evaluate the mathemat- ical characteristics of this diagnostic test. We can calculate the likelihood or probability of ﬁnding a positive test result if a person does or does not have the disease. Similarly, we can calculate the likeli- hood of ﬁnding a negative test result if a person does or does not have the disease. They can be compared in two ratios and are analogous to the relative risk in studies of risk or harm. In studies of diagnostic tests, we are looking at the probability that a person with the disease will have a positive test. We start with the likelihood of disease, do the test, and as a result of a positive test that likelihood increases. In this case, we are looking at the likelihoods of having a negative test in people with and without the disease. Their values are determined by clinical studies against a gold standard, therefore, published reports of likelihood ratios are only as good as the gold standard against which they are based and the quality of the study that determined their value. In gen- eral, one would like the likelihood ratio of a positive test to be very high, ideally greater than 10, to maximally increase the probability of disease after doing the test and getting a positive result. Similarly, one would want the likelihood ratio of a negative test to be very low, ideally less than 0. This tells the reader how sensitive the test is for ﬁnding those persons with disease when only looking at those with disease. It displays how often the result is a true positive compared to a false negative as it is the fraction of people with the disease who test positive. It is important to note that sensitivity can only be calculated from among people who have the disease. Probabilistically, it is expressed as P[T+|D+], the probability of a positive test if the person has disease. This is because in a very sensitive test, there are very few false negatives, therefore virtually all neg- ative tests must occur in non-diseased people. In addition, if the clinician has properly reduced the number of diagnostic possibilities, it would be even more unlikely that the patient has the disease in question. As a general rule, when two or more tests are available, the most sensitive one should be done to min- imize the number of false negatives. A sensitive test rules out disease – and the mnemonic is SnOut (Sensitive = ruled Out). It tells the reader how speciﬁc the test is for ﬁnding those persons without disease, when only looking at those without disease. It demonstrates how often the result is a true negative compared to a false positive, as it is the fraction of people without the disease who test negative.
Arachidonic acid and other unsaturated fatty acids are involved with regulation of gene expression resulting in decreased expres- sion of proteins that regulate the enzymes involved with fatty acid synthesis (Ou et al order 2.5mg ditropan fast delivery gastritis symptoms in puppies. This may partly explain the ability of unsaturated fatty acids to influence the hepatic synthesis of fatty acids buy cheap ditropan on-line gastritis emocional. This group includes: • 18:3 α-Linolenic acid • 20:5 Eicosapentaenoic acid • 22:5 Docosapentaenoic acid • 22:6 Docosahexaenoic acid α-Linolenic acid is not synthesized by humans and a lack of it results in adverse clinical symptoms order ditropan 5 mg online gastritis diet webmd, including neurological abnormalities and poor growth. Trans Fatty Acids Trans fatty acids are unsaturated fatty acids that contain at least one double bond in the trans configuration. The trans double-bond configura- tion results in a larger bond angle than the cis configuration, which in turn results in a more extended fatty acid carbon chain more similar to that of saturated fatty acids rather than that of cis unsaturated, double-bond– containing fatty acids. The conformation of the double bond impacts on the physical properties of the fatty acid. Those fatty acids containing a trans double bond have the potential for closer packing or aligning of acyl chains, resulting in decreased mobility; hence fluidity is reduced when compared to fatty acids containing a cis double bond. Partial hydrogena- tion of polyunsaturated oils causes isomerization of some of the remaining double bonds and migration of others, resulting in an increase in the trans fatty acid content and the hardening of fat. Hydrogenation of oils, such as corn oil, can result in both cis and trans double bonds anywhere between carbon 4 and carbon 16. In addition to these isomers, dairy fat and meats contain 9-trans 16:1 and conjugated dienes (9-cis,11-trans 18:2). The trans fatty acid content in foods tends to be higher in foods containing hydrogenated oils (Emken, 1995). There is limited evidence to suggest that the trans-10,cis-12 isomer reduces the uptake of lipids by the adipocyte, and that the cis-9,trans-11 isomer is active in inhibiting carcino- genesis. Similarly, there are limited data to show that cis-9,trans-11 and trans-10,cis-12 isomers inhibit atherogenesis (Kritchevsky et al. Dietary fat undergoes lipolysis by lipases in the gastro- intestinal tract prior to absorption. Although there are lipases in the saliva and gastric secretion, most lipolysis occurs in the small intestine. The hydrolysis of triacylglycerol is achieved through the action of pancreatic lipase, which requires colipase, also secreted by the pancreas, for activity. In the intestine, fat is emulsified with bile salts and phospholipids secreted into the intestine in bile, hydrolyzed by pancreatic enzymes, and almost completely absorbed. Pancreatic lipase has high specificity for the sn-1 and sn-3 positions of dietary triacylglycerols, resulting in the release of free fatty acids from the sn-1 and sn-3 positions and 2-monoacylglycerol. These products of digestion are absorbed into the enterocyte, and the triacyl- glycerols are reassembled, largely via the 2-monoacylglycerol pathway. The triacylglycerols are then assembled together with cholesterol, phospholipid, and apoproteins into chylomicrons. Following absorption, fatty acids of carbon chain length 12 or less may be transported as unesterified fatty acids bound to albumin directly to the liver via the portal vein, rather than acylated into triacylglycerols. Dietary phospholipids are hydrolyzed by pancreatic phospholipase A2 and cholesterol esters by pancreatic cholesterol ester hydrolase. The lyso- phospholipids are re-esterified and packaged together with cholesterol and triacylglycerols in intestinal lipoproteins or transported as lysophospholipid via the portal system to the liver. These particles enter the circulation and within the capillaries of muscle and adipose tissue. Chylomicrons come into contact with the enzyme lipo- protein lipase, which is located on the surface of capillaries. Most of the fatty acids released in this process are taken up by adipose tissue and re-esterified into triacylglycerol for storage. Triacylglycerol fatty acids also are taken up by muscle and oxidized for energy or are released into the systemic circulation and returned to the liver. Most newly absorbed fatty acids enter adipose tissue for storage as triacylglycerol. However, in the postabsorptive state or during exercise when fat is needed for fuel, adipose tissue triacylglycerol under- goes lipolysis and free fatty acids are released into the circulation. Hydrolysis occurs via the action of the adipose tissue enzyme hormone-sensitive lipase. When plasma insulin concentrations fall in the postabsorptive state, hormone-sensitive lipase is activated to release more free fatty acids into the circulation. Thus, in the postabsorptive state, free fatty acid concentrations in plasma are high; conversely, in the postprandial state, hormone-sensitive lipase activity is suppressed and free fatty acid concentrations in plasma are low. When free fatty acid concen- trations are relatively high, muscle uptake of fatty acids is also high. As in liver, fatty acids in the muscle are transported via a carnitine-dependent pathway into mitochondria where they undergo β-oxidation, which involves removal of two carbon fragments. These two carbon units enter the citric acid cycle as acetyl coenzyme A (CoA), through which they are completely oxidized to carbon dioxide with the generation of large quantities of high- energy phosphate bonds, or they condense to form ketone bodies. However, the uptake of fatty acids in excess of the needs for oxidation for energy by muscle does result in temporary storage as triacylglycerol (Bessesen et al. High uptake of fatty acids by skeletal muscle also reduces glucose uptake by muscle and glucose oxidation (Pan et al. Oxidation of fatty acids containing up to 18 carbon atoms occurs mainly in the mito- chondria. Oxidation of excess fatty acids in the liver, which occurs in pro- longed fasting and with high intakes of medium-chain fatty acids, results in formation of large amounts of acetyl CoA that exceed the capacity for entry to the citric acid cycle. During starvation or prolonged low carbohy- drate intake, ketone bodies can become an important alternate energy substrate to glucose for the brain and muscle. High dietary intakes of medium-chain fatty acids also result in the generation of ketone bodies. This is explained by the carnitine-independent influx of medium-chain fatty acids into the mitochondria, thus by-passing this regulatory step of fatty acid entry into β-oxidation. Fatty acids of greater than 18 carbon atoms require chain shortening in peroxisomes prior to mitochondrial β-oxidation. The major pathway for triacylglycerol synthesis in liver is the 3-glycerophosphate pathway, which shows a high degree of specificity for saturated fatty acids at the sn-1(3) position and for unsaturated fatty acids at the sn-2 position. Fatty acids are generally catabolized entirely by oxidative processes from which the only excretion products are carbon dioxide and water. Small amounts of ketone bodies produced by fatty acid oxidation are excreted in urine. Fatty acids are present in the cells of the skin and intestine, thus small quantities are lost when these cells are sloughed. When saturated fatty acids are ingested along with fats con- taining appreciable amounts of unsaturated fatty acids, they are absorbed almost completely by the small intestine. In general, the longer the chain length of the fatty acid, the lower will be the efficiency of absorption. Studies with human infants have shown the absorption to be 75, 62, 92, and 94 percent of palmitic acid, stearic acid, oleic acid, and linoleic acid, respectively, from vegetable oils (Jensen et al. The absorption of palmitic acid and stearic acid from human milk is higher than from cow milk and vegetable oils (which are commonly used in infant formulas) because of the specific positioning of these long-chain saturated fatty acids at the sn-2 position of milk triacylglycerols (Carnielli et al. The intestinal absorption of palmitic acid and stearic acid from vegetable oils was 75 to 78 percent compared with 91 to 97 percent from fats with these fatty acids in the sn-2 position (Carnielli et al.
Drug control resources are better categorization of cannabis cheap ditropan online mastercard gastritis with hemorrhage, coca leaf and directed elsewhere order ditropan 2.5mg on-line gastritis symptoms causes and treatment. Ensure that the international conventions are interpreted and/or revised Invest in activities that can both prevent to accommodate robust experimentation young people from taking drugs in the with harm reduction order ditropan 5 mg otc treating gastritis over the counter, decriminalization and frst place and also prevent those who do legal regulatory policies. The most successful prevention efforts may be those targeted at specifc at-risk groups. In practice, the global and wide-ranging review of strategies to respond to the scale of illegal drug markets – largely controlled by drug phenomenon. The starting point for this review is organized crime – has grown dramatically over this period. Note on Methodology: We also drew on the conclusions of a study written by eminent researchers Peter Reuter and Franz Trautmann2, and commissioned by the European The data in table 1 has been obtained from the following publications of the Union, that examined global trends across this period. Such a wide range of estimation indicates high to ‘eradicate or signifcantly reduce’ the scale of global drug markets, levels of uncertainty regarding the data. We should end the should be the reduction of harm to the health, stigmatization and marginalization of people who security and welfare of individuals and society. These are enshrined been understandable that the architects of the system in the Universal Declaration of Human Rights and many would place faith in the concept of eradicating drug international treaties that have followed. Of particular production and use (in the light of the limited evidence relevance to drug policy are the rights to life, to health, available at the time). There is no excuse, however, for to due process and a fair trial, to be free from torture ignoring the evidence and experience accumulated or cruel, inhuman or degrading treatment, from slavery, since then. These rights are inalienable, often continue to be driven by ideological perspectives, and commitment to them takes precedence over other or political convenience, and pay too little attention international agreements, including the drug control to the complexities of the drug market, drug use and conventions. Rights, Navanethem Pillay, has stated, “Individuals who use drugs do not forfeit their human rights. Too Effective policymaking requires a clear articulation of the often, drug users suffer discrimination, are forced to policy’s objectives. These improving the health of people who use drugs, they indicators may tell us how tough we are being, but they are undermining a ‘tough on drugs’ message. This is do not tell us how successful we are in improving the illogical – sacrifcing the health and welfare of one group ‘health and welfare of mankind’. Many people taking part in the drug market are themselves the victims of violence and intimidation, or are Germany dependent on drugs. An example of this phenomenon are the drug ‘mules’ who take the most visible and risky roles in Australia the supply and delivery chain. We should not treat all those arrested for Sample of countries that have introduced harm traffcking as equally culpable – many are coerced into their reduction strategies partially, or late in the actions, or are driven to desperate measures through their progress of the epidemic: own addiction or economic situation. Portugal Finally, many countries still react to people dependent on drugs with punishment and stigmatization. In reality, drug Malaysia dependence is a complex health condition that has a mixture of causes – social, psychological and physical (including, for France example, harsh living conditions, or a history of personal 0 5 10 15 20 25 30 35 40 45 trauma or emotional problems). Countries that have Sample of countries that have consistently treated citizens dependent on drugs as patients in need of resisted large scale implementation of harm treatment, instead of criminals deserving of punishment, have reduction strategies, despite the presence of demonstrated extremely positive results in crime reduction, drug injecting and sharing: health improvement, and overcoming dependence. The consistent implementation researchers in this case also referred to police of this policy has led to an overall reduction in criminal records data. The research shows the number of people addicted to heroin as well that the numbers of charges brought against as a range of other benefts. A key study14 1,476 drug users in the years before and after concluded that: entering treatment reduced by 48 percent. Heavily engaged in Heroin has lost its appeal to the mainstream youth both drug dealing and other forms of crime, they and is considered a ‘dead-end street drug’. The number of problematic heroin users has As these hard-core users found a steady, legal dropped signifcantly and the average age of users means for their addiction, their illicit drug use was has risen considerably. Large-scale, low-threshold reduced as well as their need to deal in heroin drug treatment and harm reduction services and engage in other criminal activities. The heroin substitution program had three effects on the drug market: Medically prescribed heroin has been found • It substantially reduced the consumption among in the Netherlands to reduce petty crime and the heaviest users, and this reduction in demand public nuisance, and to have positive effects on affected the viability of the market. The development and implementation of drug A current example of this process (what may be described policies should be a global shared responsibility, as ‘drug control imperialism’), can be observed with the but also needs to take into consideration diverse proposal by the Bolivian government to remove the political, social and cultural realities. Policies should practice of coca leaf chewing from the sections of the respect the rights and needs of people affected 1961 Convention that prohibit all non-medical uses. As with all multilateral agreements, the However, the idea of shared responsibility has too often drug conventions need to be subject to constant review become a straitjacket that inhibits policy development and modernization in light of changing and variable and experimentation. This analysis strenuously over the last 50 years to ensure that all and exchange of experiences is a crucial element of the countries adopt the same rigid approach to drug policy process of learning about the relative effectiveness of – the same laws, and the same tough approach to their different approaches, but the belief that we all need to have enforcement. As national governments have become exactly the same laws, restrictions and programs has been more aware of the complexities of the problems, and an unhelpful restriction. When these involve a more tolerant approach to drug use, governments have faced international diplomatic pressure to ‘protect the integrity of the Conventions’, even when the policy is legal, successful and supported in the country. These allocation, and implementation have not modernized at negative consequences were well summarized by the the same pace. The growth of a ‘huge criminal black market’, fnanced demonstrated that governments achieve much greater by the risk-escalated profts of supplying international fnancial and social beneft for their communities by demand for illicit drugs. Extensive policy displacement, the result of using scarce investing in supply reduction and law enforcement activities. Geographical displacement, often known as ‘the balloon the punishment of people who use drugs. This structure is premised on the notion that international drug control is primarily a fght against crime and criminals. Unsurprisingly, there is a built-in vested interest in maintaining the law enforcement focus and the senior decisionmakers in these bodies have 4. Drug policies must be pursued in a comprehensive traditionally been most familiar with this framework. The marginalization of the World Health system have been the police, border control and military Organization is particularly worrisome given the fact that authorities directed by Ministries of Justice, Security it has been given a specifc mandate under the drug or Interior. Caitlin Hughes of the University of New strategies will not solve the drug problem, and South Wales and Professor Alex Stevens of the University that the war on drugs has not, and cannot, be won. Hughes and Stevens’ 2010 report detects a slight increase in overall rates of drug use in Portugal in the 10 years since 2. Replace the criminalization and punishment of decriminalization, but at a level consistent with other similar people who use drugs with the offer of health and countries where drug use remained criminalized. Their overall conclusion is that was that the threat of arrest and harsh punishment the removal of criminal penalties, combined with the use would deter people from using drugs. In practice, of alternative therapeutic responses to people struggling this hypothesis has been disproved – many countries with drug dependence, has reduced the burden of drug law that have enacted harsh laws and implemented enforcement on the criminal justice system and the overall widespread arrest and imprisonment of drug users and level of problematic drug use. The researchers wished to examine whether the more repressive policy environment of San Francisco deterred citizens from smoking cannabis or delayed the onset of use.
It is useful to outline the erythema fascial compartments discount ditropan 5mg overnight delivery gastritis hiv symptom, and meticulous debridement of to allow the condition to be followed order 5mg ditropan with mastercard acute gastritis symptoms treatment. Clostridial myonecrosis (gas gangrene) Deﬁnition Leprosy Gangrenereferstodeathoftissue purchase ditropan cheap gastritis blog,andmyonecrosisrefers speciﬁcally to muscle. Clostridial infection of wounds Deﬁnition may result in signiﬁcant infection of muscle, which de- Leprosy is a chronic indolent mycobacterial infection velops rapidly and is potentially life-threatening. Com- Geography promise of the blood supply as a result of the traumatic Leprosy is found primarily in Africa and Asia. It is thought that τ-toxin pro- Leprosy is caused by an intracellular acid-fast bacillus, duced by Clostridium prevents the normal inﬂamma- Mycobacterium leprae. The mode of transmission is un- tory cell inﬁltration and therefore allows the infection certain and the incubation may be many years. Fivepatternsofdiseasearerecognisedthataredependent on the immunological response of the individual (see Clinical features Table 9. Patients develop severe pain due to myonecrosis at a site There are two immunological reactions that may oc- of trauma with induration, blistering and oedema. It is characterised by fever and mul- most individuals are seropositive by adult life. Im- munocompromised patients are at particular risk for recurrent and disseminated infection. Afterprimary infection, the latent non-replicating virus resides within the dorsal root ganglion, shielding the Management virus from the immune system. Symptomatic infection usually manifests as acute gingivostomati- tis with vesicles on the lips and painful ulcers within Viral skin infections the mouth accompanied by fever and malaise. Local herpes inoculation into a site of injury may present Herpes simplex as a herpetic whitlow–apainful vesicle or pustule on a digit. Ocular infections and encephalitis (see page Deﬁnition 304) may occur with or without kin lesions. Aetiology/pathophysiology Latent infection occurs and recurrence is often her- There are two subtypes: alded by a burning or tingling sensation. It usually Chapter 9: Infections of the skin and soft tissue 401 occurs at the site of the primary infection and in ad- the rash. Theyheal Patients with atopic eczema may develop eczema her- over 2–3 weeks leaving scars. Corneal ulcers and corneal scarring may result from trigeminal infection with ocular involvement. Topical treat- therpetic neuralgia is found in 5–10% of patients pre- ment at the onset of tingling may prevent a recur- senting as a continued burning pain. As aciclovir works to prevent reactivation it is of limited value in established disease. However, immuno- Investigations suppressed patients should be treated aggressively with The virus can be isolated from vesicular ﬂuid and iden- parenteral aciclovir to prevent dissemination. Aciclovir is effective in Deﬁnition shortening the duration of pain when started within Herpes zoster or shingles is an acute self-limiting der- 48 hours of the onset of the rash. It should be given matomal vesicular eruption occurring in a dermatomal parenterally in the immunocompromised. Human papillomavirus (viral warts) Incidence Affects 10–20% of the population at some time in their Deﬁnition lives. Like other herpes virus infections, it are high-risk subtypes for neoplasia and are associated then remains as a latent infection in the sensory dorsal with cervical and oral cancer. Clinical features 1 Common warts are well-demarcated dome shaped Clinical features papules or nodules with an irregular papilliferous sur- Pain,tendernessorparaesthesiadevelopsinthedistribu- face. Commonly occur on the back of hands, between tion of a single dermatome 3–5 days prior to the onset of ﬁngers and around the nail edge. No treatment is universally successful, and as there is a Patients present with an inﬂamed glans and prepuce. Management Topical antifungals are used in the form of creams, Prognosis lozenges or pessaries. Fungal skin infections Dermatophyte (ring worm) fungi Candida albicans Deﬁnition Deﬁnition Dermatophytes or ringworm fungi invade keratin and Candida albicans,acommensal yeast of the gastroin- cause skin and nail infections. Aetiology/pathophysiology Lesions are single or multiple erythematous, scaly, Candida is a dimorphic fungus occurring as a yeast on well-demarcated patches on the scalp that gradually mucosal surfaces. Hairs within the patch break off giving a patch infections result from disruption of the normal body of alopecia. It is a form of immune response tend towards more extensive persistent mucous mem- to the fungus. Neutropenic patients are at risk of itraconazole or griseofulvin are effective even in ke- widespread disseminated illness. Patients develop itchy or painful, erythematous scaling lesions between the Clinical features toes. It may be acute self-limiting or a persistent 1 Oral candidiasis is commonly seen in babies and chronic infection. Topical antifungal agents are usu- patients treated with antibiotics or chemotherapy. Chapter 9: Infections of the skin and soft tissue 403 r Tinea Unguium: Nail infection with ringworm is Management common especially in the elderly. Patients develop Topical shampoo containing insecticides such as mala- asymmetrical discoloured (white/yellowish black) thion and permethrin may be used, although there thickened nails with crumbling white material un- is some evidence of increasing resistance. Mechanical removal of prolonged course of systemic antifungals as for tinea lice nit combs from wet hair is an alternative strategy. Household members should be examined and treated if r Tinea Cruris: Tinea cruris affects the groin with ery- infested. Severe or refractory cases require oral antifungals as for tinea Deﬁnition capitis. Parasitic skin infections Aetiology/pathophysiology Transmission of the mite occurs by skin–skin contact Head lice with an infested individual or contaminated clothing or bedding. The mite burrows down into the stratum Deﬁnition corneumofthe skin and then the female lays eggs. Clinical features Incidence r There is often a widespread, erythematous urticating Common rash all over the body as a result of a hypersensitiv- ity reaction to the mite. Age r On examination small papules and linear tracks, Occurs mainly in school children. Pediculosiscapitis orheadlouseisagrey-whiteinsectthat grasps on to hair and sucks blood. Insects are spread by contact The burrows and distribution pattern is very suggestive but as insects can survive for hours away from the host, of the diagnosis. The mite can be visualised using a der- transfer on clothing, shared combs, towels and beds may matoscope. Management Clinical features Patients are extremely infectious and require barrier Infestations are often asymptomatic although allergy nursing.