There are around 4,000 possible dermatological diagnoses, yet in primary care four conditions – acne, eczema, psoriasis and leg ulcers – account for nearly three quarters of all consultations. Other conditions encountered include viral, bacterial and fungal infections, as well as benign and malignant skin lesions.
Although impossible for pharmacists to be familiar with every diagnosis, a systematic approach can often help to narrow the diagnosis and identify a likely cause. It is necessary therefore for pharmacists to undertake a complete dermatological history when assessing patients with skin problems.
A systematic approach to questioning the patient will often help to establish the cause. In addition to the suggested questions it is worth enquiring about:
Examining the patient
Once a history has been taken it is necessary to examine the rash or lesion. This should ideally be undertaken in daylight, or at least with a good light source. Important factors to consider include:
The language of dermatology
As in other areas of medicine, pharmacists need to be familiar with the language of dermatology. The effect of a problem on the skin surface also involves a number of specific descriptors:
Conditions affecting the face
Common problems occurring on the face in children include atopic eczema, impetigo and herpes simplex. Differentiating between impetigo and herpes simplex can be difficult in the early stages (see flow chart). A clue to diagnosing atopic eczema is that other body sites, such as the elbow flexures and behind the knees, are often also affected.
Common facial problems in adults include acne, rosacea and seborrhoeic eczema. Both acne and rosacea can have inflamed papules and pustules. In rosacea, the papules and pustules are present on an erythematous background, occurring typically on the cheeks, forehead and chin. Acne can be distinguished from rosacea by the presence of comedones, which are absent in rosacea. Furthermore, although acne can and does persist into middle age, rosacea tends to first present in the second or third decade.
Seborrhoeic dermatitis is a scaly erythematous rash which affects the central area of the face, eye brows and beard area. It also causes a greasy and scaly scalp and can occur in flexural sites as well-defined, shiny erythematous lesions. Seborrhoeic eczema occurs in babies as cradle cap. The main differential is psoriasis, although seborrhoeic dermatitis does not cause scaling on extensor surfaces or affect the nails. However, some specialists maintain that seborrhoeic eczema is a milder form of psoriasis, often referred to as ‘sebopsoriasis’. Patients with seborrhoeic dermatitis often find their condition flares during the winter months or during periods of illness and stress, which is a potential clue to the diagnosis.
There are a number of possible causes of childhood rashes and it is beyond the scope of this article to discuss all of them. Many rashes in children are associated with systemic symptoms such as headache, fever or general malaise, in which case the rash is referred to as an exanthem.
Again, there are many causes of rashes in adults and some overlap with rashes in children.
There are several different skin lesions, some of which are benign and others which are malignant or have the potential to become malignant. If pharmacists are unsure patients should always be referred to the GP.
Questions to ask a patient who presents with a skin problem
Taking a history is extremely important in trying to establish the diagnosis. Asking the patient the following questions will help to establish the cause of the problem:
Dr Rod Tucker is a community pharmacist, visiting research fellow studying the role of pharmacists in the management of eczema at the Institute of Health Sciences, University of Leeds, and a project guardian for the CPPE dermatology packages