How Pharmacist Diagnosis a Patient

How Pharmacist Diagnosis a Patient

Global health care policy now has a strong self-care focus, and various strategies have been put into place to encourage consumers to have a more active role in exercising self-care.

Pharmacies unquestionably handle and manage large numbers of consumers who seek help and advice for minor illness, and advocates of pharmacy have argued that this will decrease physicians’ workloads regarding minor illness, allowing them to concentrate more on complex patient care.

The expansion of nonprescription medicines has contributed to the growth seen in the market and given consumers greater choice. It has also provided community pharmacy with an opportunity to demonstrate real and tangible benefits to consumers. For example, in the UK, government-endorsed (and funded) services such as Minor Ailment Schemes have shown the positive impact that community pharmacy can have on patient outcomes. However, research data on the effectiveness of community pharmacy staff to differentially diagnose patients is less convincing.

How Pharmacist Diagnosis a Patient

Community pharmacy performance when dealing with patients’ signs and symptoms

Regardless what degree of control is placed on medicine availability in different countries, pharmacists can now man-age and treat a wider number of conditions than ever before. This raises the question as to whether pharmacists are capable of selling these medicines appropriately. Early research of pharmacist-consumer interactions in pharmacy practice did not address this but concentrated more on auditing questioning behaviour and analysing the advice people received (Cantrill etal., 1997). This body of work did illustrate the fol-lowing: the basic nature of performance; types of questions asked; frequency of advice provided; and consumer perception to questioning. The findings were broadly critical of pharmacist performance. Over the same time period, covert investigation by the UK consumer organization, ‘Which’, also concluded that pharmacists generally performed poorly.(Consumers’ Association, 1999).
Further practice research (mainly from developed countries) has sought to determine the outcome of these interactions rather than the mechanics of the interaction. Findings from all papers raise questions over pharmacist ability to consistently perform at expected levels. Lamsam & Kropff (1998), found that in one-third of interactions, the pharmacists made recommendations without assessing the patient’s symptoms and, in a further third of cases, recommendations were poor, which could have potentially caused harm. Horsley etal. (2004) found that the expected outcome was only reached in half of observed cases. Driesen and Vandenplas (2009) and Bilkhuetal. (2013) also reported poor performance, and in each study – diarrhoea in a baby and allergic conjunctivitis in an adult – it was suggested that too few questions were asked. Tucker etal. (2013) compared pharmacist performance to doctors and nurses across a spectrum of dermatological conditions. Pharmacists performed more poorly than doctors, and only 40% of pharmacists were able to identify all lesions correctly. Data from developing couttries are limited but a review by Brata et al. (2013) also highlighted inconsistent information gathering, leading to inappropriate recommendations.

Current pharmacy training in making a diagnosis

The use of protocols, guidelines and mnemonics seem to have been almost universally adopted by pharmacists. Many mnemonics have been developed, as highlighted in a 2014 review (Shealy, 2014). The use of these decision aids seems to have had little impact on improving performance, and recent research findings have shown that community pharmacists overrely on using this type of questioning strategy (Akh-tar & Rutter, 2014; Iqbal & Rutter, 2013; Rutter & Patel, 2013).
Do not use mnemonics: 
At best, these tools allow for standardizing information gained from patients from and between pharmacists and the wider pharmacy team. The more fundamental and important point is not simply asking questions but determining how that information is used. Having a set of data still requires interpretation, and this inability to synthesize gath-ered information appropriately is where research has highlighted pharmacists’ failings.
Mnemonics are rigid, inflexible and often inappropriate. Every patient is different, and it is unlikely that a mnemonic can be fully applied and, more importantly, using mnemonics can mean that vital information is missed, which could shape decision making. Some of the more commonly used mnemonics are discussed briefly in the next section.

This is the most common mnemonic in use and is widely taught and used in the UK. It is the simplest to remember but also the worst to use. It gives the pharmacist very limited information from which to establish a differential diagnosis. If used, it should be used with caution and is probably only helpful as a basic information-gathering tool. WWHAM might be appropriate to allow for counter assistants to gain a general picture of the person’s presenting complaint but should not be advocated as a tool to establish a diagnosis.

Meaning of the letter                                   Attributes of the mnemonic
W Who is the patient?                                     Positive points
W What are the symptoms?                             Establishes presenting complaint 
H How long have the symptoms been present?  Negative points
A Action taken?                                               Fails to consider general
M Medication being taken?                               appearance of patient. No social                                                                         lifestyle factors taken into     
                                                                     account; no family history 
                                                                     sought; not specific or in-depth 
                                                                     enough; no history of previous s                                                                        symptoms

Other examples of mnemonics that have been suggested as being helpful for pharmacists in a differential diagnosis are ENCORE, ASMETHOD and SIT DOWN SIR. Although these are more comprehensive than WWHAM, they still are limited. None take into consideration all factors that might affect a differential diagnosis. All fail to establish a full history from the patient with respect to lifestyle and social factors or the relevance of a family history. They are designed to establish the nature and severity of the presenting com-plaint, which in many cases will be adequate but for intermittent conditions (e.g., irritable bowel syndrome, asthma, hay fever) or conditions where a positive family history is important (e.g., psoriasis, eczema), they might miss important information that is helpful in establishing the correct diagnosis.

Meaning of the letter                                   Attributes of the mnemonic

E Explore                                                  Positive points 
N No medication                                        Observe’ section suggests taking                                                                        into   account the appearance of the 
                                                                patient – does he or she look poorly?

C Care                                                      Negative points: Sections on ‘No
O Observe                                                 medication’ and ‘Refer’ add little to 
R Refer                                                     the differential diagnosis process; no 
E Explain                                                   social or lifestyle factors taken into 
                                                                account; no family history sought

Meaning of the letter                                   Attributes of the mnemonic

A Age, appearance                                          Positive points: Establishes the 
                                                                     nature of problem and if patient
                                                                     has suffered from previous                                                                                 similar episodes
S Self or someone else                                    social or lifestyle factors not taken
                                                                     into account; no family history 
M Medication
E Extra medicines
T Time persisting
H History
O Other symptoms 
D Danger symptoms

Meaning of the letter                                   Attributes of the mnemonic

S Site or location                                             Positive points Establishes the   
I Intensity or severity                                      severity and nature of problem  
T Type or nature                                              and if the patient has suffered
D Duration                                                      from previous similar episodes   
O Onset
W With (other symptoms)
N Annoyed or aggravated
S Spread or radiation                                        Negative points
I Incidence or  frequency pattern                       Fails to consider general 
R Relieved by                                                   appearance of patient; no 
                                                                      social or lifestyle factors taken
                                                              into account; no family history sought

Clinical reasoning

Decision making processes associated with clinical practice are an essential skill and are central to the practise of professional autonomy. Clinical reasoning is the cornerstone on which a diagnosis is made and relies on the practitioner being both knowledgeable and a good decision-maker. Clinical reasoning is an evidence-based, dynamic process in which the health professional combines scientific knowledge, clinical experi-ence and critical thinking, with existing and newly gathered information about the patient against a backdrop of clinical uncertainty. It is a thinking process that allows the pharmacist to make wise decisions specific to individual patient context.

Whether we are conscious of it or not, most people will, at some level, use clinical reasoning to arrive at a differential diagnosis. It fundamentally differs from using mnemonics in that it is built around clinical knowledge and skills that are applied to the individual patient. It involves recognition of cues and analysis of data.

Steps to consider in clinical reasoning

1. Use epidemiology to shape your thoughts.
What is the presenting complaint? Some conditions are much more common than others. Therefore, you can form an idea of what condition the patient is likely to be suffering from based on the laws of probability. For example, if a person presents with a cough, you should already know that the most common cause of cough is a viral infection. Other causes of cough are possible and need to be eliminated. Your line of questioning should therefore be shaped by thinking that this is the default cause of the person’s cough and ask questions based on this assumption (see step 4, below).

2. Take account of the person’s age and sex Epidemiological studies show that age and sex will influence the likelihood of certain conditions. For example, it is very unlikely that a child who presents with cough will have chronic bronchitis, but the probability of an elderly person having chronic bronchitis is much higher. Likewise, croup is a condition seen only in children. Sex can dramat-ically alter the probability of people suffering from certain conditions. For instance, migraines are three times more common in women than in men, yet cluster headache is four times more common in men than in women. Use this to your advantage. It will allow you to internally change your thought processes as to which conditions are most likely for that person.

3. General appearance of the patient
Does the person look well or poorly? This will shape your thinking about the severity of the problem. If a child is running around a pharmacy, they are likely to be health-ier than a child who sits quietly on a chair, not talking. Taking these three points into consideration, you should be able to form some initial thoughts about the person’s health status and ideas of what may be wrong with them. At this point, questions should be asked.

4. Hypothetical-deductive reasoning
Based on this (limited) information, the pharmacist should arrive at a small number of hypotheses. The phar-macist should then set about testing these hypotheses by asking the patient a series of questions.
Ask the right question, at the right time, for the right reason
The answer to each question asked allows the pharmacist to narrow down the possible diagnosis by eliminating particular conditions or confirming his or her suspicions of a particular condition. In effect, the pharmacist asks questions with knowledge of the expected answer. For example, a confirmatory type of question asked of a patient suspected of having allergic conjunctivitis might be ‘Do your eyes itch?’ In this case, the pharmacist is expecting the patient to say ‘yes’ and thus helps support your differential diagnosis. If a patient states ‘no’, this is an unexpected answer that casts doubt on the differen-tial diagnosis; therefore, further questions will be asked and other diagnostic hypotheses explored. This cycle of testing and retesting the hypotheses continues until you arrive at a differential diagnosis.
Good questioning following these principles means that you will end up with the right diagnosis about 80% of the time.

5. Pattern recognition
In addition, clinical experience (pattern recognition) also plays a part in the process. Certain conditions have very characteristic presentations and, with experience, it is relatively straightforward to diagnose the next case drawing on previous cases seen. Therefore, much of daily practice will consist of seeing new cases that strongly resemble previous encounters and comparing new cases to old.
Pattern recognition is therefore much more commonly used by experienced or expert diagnosticians compared with novices. This is generally because there is a gap between the expert-novice knowledge and clinical experience. Research has shown that experienced doctors tend to only use hypothetical-deductive strategies when presented with difficult cases.

6. Physical examination
The ability to perform simple examinations (e.g., eye, ear, mouth and skin examinations) increases the probabilty of arriving at the correct diagnosis. Where appropriate (provided that pharmacists are suitably trained), examinations should be conducted. Seeing a rash or viewing an eardrum will provide much better data on which to base a decision than purely a patient description. Through-out this text, where examinations are possible, instruction is given in how to perform these examinations. Student consult has some videos on how to perform these physical examinations.

7. Safety netting
Even if you are confident of your differential diagnosis, it is important to use a safety net. You are not going to get it right all the time; making an incorrect diagnosis is inevita-ble. It has been reported that more than 50% of patients do not receive a definitive diagnosis at the end of a consultation with a family doctor (Heneghan et al., 2009). Many people will present to the pharmacist at an early stage in the evolution of their illness. This means that they may not present with classical textbook symptoms or have not yet developed any red flag – type symptoms when seen by the pharmacist. For example, a child may have a headache but no other symptoms yet later go on to develop a stiff neck and rash and be diagnosed with meningitis, or a person may have an acute cough that subsequently develops into pneumonia. Using a safety net attempts to manage these situations.

This should take one of two forms:
Conditional referrals
This should be built into every consultation. It is more than a mere perfunctory ‘If you don’t get better come back to me or see the doctor’. It has to be tailored and specific to the individual and the symptoms. For example, if apers on presents with a cough of 10 days’ duration, after how many more days would you ask them to seek further medical help – 3 days? 5 days? 7 days? Longer?

In this case, knowledge of cough duration is important. If the differential diagnosis is a viral cough, then we know that this symptom typically lasts 10 to 14 days, but it is not unusual for the symptom to last 21 days. Longer than 21 days suggests that the cough is becoming chronic and requires further investigation. A conditional referral in this case would be any-thing between 5 and 10 days; in other words, the person has had the cough for between 2 and 3 weeks, which is starting to become longer than one would expect for a viral cough. Conversely, if the cough had been present for just 2 days, a conditional referral after a further 2 more weeks would be appropriate.

Advise patients on warning symptoms

It is entirely reasonable to highlight to patients signs and symptoms that they may develop subsequent to your consultation. For example, a child suffering with diarrhoea is managed by the pharmacist, but the pharmacist highlights the signs of dehydration to the child’s parents. This would be good practice because the consequence of dehydration is clinically more significant than the diarrhoea itself.


In practice, family doctors tend to use a mixture of hypotheticodeductive reasoning and pattern recognition augmented with physical examination and, where needed, laboratory tests. It can seem to some patients that the doctor asks very few questions, spends very little time with them, and closes the consultation even before they have ‘warmed the seat’. In these cases, the doctor is probably exhibiting very good clinical reasoning. Research has shown that with greater experience, doctors tend to rely more on nonanalytical decision making (e.g., pattern recognition), whereas nov-ice practitioners use analytical models (hypotheticodeductive reasoning) more frequently.
Most pharmacists will exhibit some degree of clinical reasoning but most likely at a subconscious level. The key to better performance is shifting this activity from the subconscious to conscious. Gaining clinical experience is fundamental to this process. Critical for pharmacists is the need to learn from uncertainty. When referrals are made, every attempt should be made to follow up with the doctor about the outcome of the referral or encourage the patient to return to the pharmacy to see how they got on. Knowing what another person (usually a more experienced diagnostician) believed what the diagnosis was allows you to build up experience and, when faced with similar presenting symptoms, have a better idea of the cause. Without this feedback, pharmacists reach a ‘glass ceiling’, where the outcome is always the same – referral – which might not be necessary.

Differential diagnosis – an example

A 35-year-old female patient, Mrs JT, asks to speak to the pharmacist about getting some painkillers for her headache. She appears smartly dressed and in no obvious great discomort but appears a little distracted.
Step 1: Use epidemiology to shape
your thoughts
In primary care, headache is a very common presenting symptom that can have many causes. Table 1.1 highlights the conditions associated with headache that can be seen by community pharmacists.
From this background information, you should already be thinking that the probability of Mrs JT’sheadaches are going to be caused by the four conditions that are commonly seen by community pharmacists – tension-type headache, migraine, sinusitis and eye strain. This is not to say that it could not be caused by the other conditions, but the likelihood that they are the cause is much lower.
Step 2: Take account of the person’s age and sex
Does age or sex have any bearing on shaping your thoughts? The person is a woman, and we know that migraines are more common in women compared with men. So, although tension-type headache is the most common cause of headache, the chances of it being caused by migraine needs to be given more prominence in your thinking. Will age affect your thinking? In this case, probably not, because the common causes of headache do not really show any real variation with age.
At this point, you should still be considering all four con-ditions as likely, but migraine as a cause should now be thought of more seriously along with the most common cause of headache: tension.

Step 3: The general appearance of the patient
Nothing obvious from her physical demeanour is constructive regarding your thinking. Her ‘distracted’ state might be as a consequence of the pain from the headache and worth exploring.
Step 4: Hypotheticodeductive reasoning
Each question asked should have a purpose; again, it is about asking the right question, at the right time and for the right reason. In this case, we are initially considering the conditions of tension-type headache, migraine, sinusitis and eye strain (listed in that sequence in terms of likelihood). It is important that your clinical knowledge be sufficiently sound to know how these different conditions present so that similarities and differences are known, allowing questions to be constructed to eliminate one type of headache from another. This will allow you to think of targeted questions to ask. Table 1.2 highlights associated signs and symptoms of these four conditions.
We can see that the location and nature of pain for the four conditions vary, as do the severity of pain experienced (although pain is subjective and difficult to measure reliably).
A reasonable first question would be about the location of pain. If the patient says, ‘It is bilateral and towards the back’, this points towards the tension-type headache (other causes are frontal or unilateral).
Given this information, if we asked about the nature of pain next, and working on the hypothesis of tension-type headache, we would be expecting a response from the patient of an ‘aching, nonthrobbing headache’, which might worsen as the day goes on. If patients describe symptoms similar to our expectation, this further points to tension-type headache as being the correct diagnosis.
To further confirm your thinking, you could ask about the severity of pain. In tension-type headache, we are expecting a response that does not suggest debilitating pain. Again, if we found that the pain was bothersome but not severe, this would point to tension-type headache.
At this point, we might want to ask other questions that rule out other likely causes. We know that migraine is associated with a positive family history. We would expect the patient to say there was no family history if our working differential diagnosis is tension-type headache. Likewise, asking about previous episodes of the same type of headache would help rule out migraine due to its episodic and recurrent nature. Similarly, eye strain is closely associated with close visual work. If the person has not been doing this activity more than normal, it tends to rule out eye strain. Finally, sinusitis is a consequence of upper respiratory tract infection so, if the person has not had a recent history of colds, this will rule out sinusitis.

Therefore, we are expecting certain responses to these questions if the symptoms are a consequence of suffering from a tension-type headache. If the patient answers in a negative way, this would start to cast doubt on your differential diagnosis. If this happens, you need to revisit your hypothesis and test another one – that is, think that the symptoms are caused by something else, and recycle your thought processes to test a hypothesis of a different cause of headache.

Consultation and communication skills

The ability of the community pharmacist to diagnose the patient’s presenting signs and symptoms is a significant challenge given that unlike most other healthcare professionals, community pharmacists do not normally have access to the patient’s medical record and thus have no idea about the person’s problem until a conversation is initiated.
For the most part, pharmacists will be totally dependent on their ability to question patients to arrive at a differential diagnosis. It is therefore vital that pharmacists possess excel-lent consultation and communication skills as a prerequisite to determining a differential diagnosis. This will be drawn from a combination of good questioning technique, listening actively to the patient and picking up on nonverbal cues.
Many models of medical consultation and communication have been developed. Probably the most familiar and most widely used model is the Calgary Cambridge model of consultation. This model is widely taught in pharmacy and medical education and provides an excellent platform in which to structure a consultation. The model is structured into the following:

1. Initiating the session
 Establishing initial rapport
 Identifying the reason(s) for the consultation
2. Gathering information
 Exploration of problems
 Understanding the patient’s perspective
 Providing structure to the consultation
3. Building the relationship
 Developing rapport
 Involving the patient
4. Explanation and planning
 Providing the correct amount and type of information
 Aiding accurate recall and understanding
 Achieving a shared understanding: Incorporating the patient’s perspective
 Planning: Shared decision making
 Closing the session
For more detailed information on this model, there are numerous Internet references available, and the authors of the model have written a book on communication skills (Silvermanetal., 2013).


The way in which one goes about establishing what is wrong with the patient will vary from practitioner to practitioner. However, it is important that whatever method is adopted, it must be sufficiently robust to be of benefit to the patient. Using a clinical reasoning approach to differential diagnosis has been shown to be effective in differential diagnosis and is the method advocated throughout this book.


Akhtar, S., & Rutter, P. (2015). Pharmacists thought processes in making a differential diagnosis using a gastrointestinal case vignette. Research in Social and Administrative Pharmacy, 11(3), 472–479.

Bilkhu. P., Wolffsohn, J. S., Taylor, D., et al. (2013). The

management of ocular allergy in community pharmacies in the United Kingdom. International Journal of Clinical Pharmacy, 35, 190–194.

Brata, C., Gudka, S., Schneider, C. R., et al. (2013). A review of
the information-gathering process for the provision
of medicines for self-medication via community pharmacies in developing countries. Research in Social and Administrative Pharmacy, 9, 370–383.
Cantrill, J. A., Weiss, M. C., Kishida, M., et al. (1997). Pharmacists’

perception and experiences of pharmacy protocols: A step in the right direction? International Journal of Clinical Pharmacy, 5,26–32.
Consumers’ Association. (1999). Counter advice. Which Way to
Health? 3,22–25.
Driesen, A., & Vandenplas, Y. (2009). How do pharmacists
manage acute diarrhoea in an 8-month-old baby? A simulated client study. International Journal of Clinical Pharmacy, 17, 215–220.
Horsley, E., Rutter, P., & Brown, D. (2004). Evaluation of community
pharmacists’ recommendations to standardized patient scenarios. The Annals of Pharmacotherapy, 38,1080–1085. Iqbal, N., & Rutter, P. (2013). Community pharmacists reasoning
when making a diagnosis: A think-aloud study. International Journal of Pharmacy and Practice, 21,17–18.
Lamsam, G. D., & Kropff, M. A. (1998). Community pharmacists’
assessments and recommendations for treatment in four case scenarios. The Annals of Pharmacotherapy, 32, 409–416. Rutter, P., & Patel, J. (2013). Decision making by community
pharmacists when making an over-the-counter diagnosis in
response to a dermatological presentation. Self Care, 4,125–133.
Shealy, K. M. (2014). Mnemonics to assess patients for self-care:
Is there a need? Self Care, 5,11–18.
Silverman, J., Kurtz, S., & Draper, J. (2013). 3rd ed. Boca Raton, FL:
CRC Press.
Tucker, R., Patel, M., Layton, A. M., et al. (2013). An examination
of the comparative ability of primary care health professionals in the recognition and treatment of a range of dermatological conditions. Self Care, 4,87–97.
Which? Can you trust your local pharmacy’s advice? http://www. Accessed 17th March 2020
Further reading
Aradottir, H. A. E., & Kinnear, M. (2008). Design of an algorithm to
support community pharmacy dyspepsia management. Pharmacy World and Science, 30, 515–525.
Bertsche, T., Nachbar, M., Fiederling, J. (2012). Assessment of a
computerised decision support system for allergic rhino conjunctivitis counselling in German pharmacy. International Journal of Clinical Pharmacy, 34,17–22.

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