Dermatological History and Examination

Skin disease is marked by its variety and visibility. Dermatology is a field where pattern recognition and analysis is critical so experience is key - having seen something previously makes it much easier to recognise it in the future. Accurate history and examination is as important in dermatology as in any other field of medicine. A systematic approach is required, although this may become truncated with experience, but even the most experienced doctor will have the occasional difficult case where it is necessary to go back to basics.

The diagnosis and management of skin disease makes up a large component of Primary Care and most GPs develop diagnostic and surgical skills to deal with this demand. In recent years, nurses have been more involved in the provision of dermatological care¹ as well as having to make diagnoses in circumstances such as a walk in clinic.²

As always this is the starting point:

• What is the problem?
• Note the age of the patient. Infectious diseases are more common in children. Malignancy gets more common with advancing age. Many diseases have a typical age of onset.
• Where is or are the lesions? As well as skin, remember mucous membranes. The site of lesions is important. Eczema tends to be on flexural surfaces (in adults and older children) whilst psoriasis tends to be on extensor parts. Lesions may have a specific distribution - around the genitals, in sweaty regions or sun-exposed areas.
• Was there a sudden or gradual onset of the skin condition? Is this an acute presentation or an ongoing chronic problem? Is this a recurrence of a previous problem - with a previous episode, a patient may already have been given a diagnosis.
• It is changing? Urticaria may be quite dynamic in its presentation but others are much more static.
• Is it itchy? Some lesions are renowned for being itchy and others for not being so but this can be misleading. Psoriasis is said to be non-itchy but there may be pruritus in the genital area.
• Is it tender? Inflammation is often tender.
• Does it bleed or discharge? Bleeding may indicate malignancy. Discharge may occur with an infected lesion.
• Are there any aggravating or relieving factors? Heat and cold may be either aggravating or relieving factors, especially with urticaria.
• Are there any systemic symptoms such as pyrexia or malaise? Pyrexia suggests an infection.
• How has general health been recently? Skin lesions may be a feature of a systemic disease with malaise. People with shingles often feel unwell. Some skin lesions are markers for underlying malignancy.³
• Have you tried to treat it yourself? The patient may already have used calamine, antihistamines, or rather nebulous remedies like witch hazel. They may have had access to steroid cream. They may have used complementary medicines such as chinese herbs⁴ with varied ingredients and potency. Partially treated lesions are the most difficult to diagnose.

Do not forget to cover:

• Family history - this may indicate a familial trend for the disease. Other family members will have been given a diagnosis. A genetic predisposition is important in many diseases including eczema and psoriasis. Alternatively, concurrent and recent affliction of other members of the family suggests a contagious or environmental aetiology.
• Occupation, hobbies and pastimes - there may be exposure to chemicals or a very hot environments, for example.⁵
• Travel - particularly to exotic locations.^6,7
• Drugs, prescribed, OTC or other therapies. Drug eruptions can be highly variable.⁸
• Smoking and alcohol - alcohol use has an association with psoriasis⁹ and smoking increases the risk of some malignancies.
• Allergies
• Psychological and social sequelae - people with severe, chronic, visible and disfiguring skin disease may suffer from anxiety, depression and social isolation, these issues require exploration.¹⁰ The problems of Living with Skin Disease are discussed elsewhere.

First just look:

• Does the patient look ill or well? Are there any clues as to systemic illness?
• Wipe off any calamine, make up or anything else that may obscure the true nature of the lesions.

Now focus on the lesion(s):

• Note the position of lesions:
  • Flexor or extensor surfaces?
  • Areas of friction or pressure?
  • Sweaty regions?
  • Exposed regions?
  • Related to sexual contact? (consider genital lesions but also lower abdomen and upper thighs)
• Note the size of the lesion. Measure for accuracy.
• Is it single or multiple?
• Is there a characteristic distribution as with shingles?
• If a rash, what is the nature? It may be:
  • Macular
  • Papular
  • Vesicular
  • Crusty
  • Urticarial
• Note colour, shape, regularity or irregularity. Are there areas of inflammation around it? Is the edge clearly demarcated or poorly defined?

• Note:
  • Tenderness
  • Warmth
  • Consistency (hard, soft, firm, fluctuant)
• Does firm pressure lead to blanching?
• Is it friable? Does it bleed easily?
• If appropriate, look to see if there is any evidence of infestation.
• Note hair in the local skin and on the head.
• Look at the nails.¹¹
• Are mucous membranes involved?¹²
• Are there regional lymph nodes? This may be relevant for infectious or malignant lesions.

Having completed the full history and examination it is usually possible to make a firm diagnosis but, if not, it is certainly possible to distil a great deal of information about the condition. Very often the impressive names that dermatologists give to unusual conditions are nothing more than a description in Latin. Where a firm diagnosis cannot be made with a reasonable degree of confidence then investigations may be helpful and even a therapeutic trial may be worthwhile. However, steroid cream can mask some aspects of a disease and dermatologists often complain of the difficulties of diagnosing partially treated disease. Teledermatology is fundamentally changing primary care's access to an expert opinion on a skin condition although concerns persist about reduced diagnostic reliability and the ongoing need for face-to-face consults, particularly in the diagnosis of skin malignancies.¹³

One of the most important decisions to make about a skin lesion is whether or not it is malignant.¹⁴ There must be a high index of suspicion. Absolute certainty is rare. The following guide applies particularly to pigmented lesions.

Wood's light

This is a useful tool to have available in a surgery - it is an ultraviolet light (wavelength 360-365 nm) used in a darkened room. It should be held at least 10-15 cm from the skin and time should be allowed for dark accommodation to occur.
When shone on some fungal infections, the light causes fluorescence. Tinea versicolor fluoresces with subtle gold colours, and erythrasma due to Corynebacterium minutissimum fluoresces a bright coral red. Tinea capitis caused by Microsporum canis and Microsporum audouinii fluoresce a light bright green but most tinea capitis infections are caused by Trichophyton species that do not fluoresce. The earliest sign of Pseudomonas aeruginosa infection, especially in burns, may be green-yellow fluorescence.
Vitiligo also fluoresces. Its associated depigmentation can be differentiated from hypopigmented lesions by the ivory-white colour under Wood's light.
Wood's light can also be used in the evaluation of pigmented lesions, marking out areas of lentigo maligna or melasma.¹⁶

Skin scrapings

Skin scrapings for microscopy can be useful to diagnose fungal infections, pityriasis versicolor and ectoparasitic infections such as scabies. For dermatophyte infections, scrape the advancing edge of the scaly lesion carefully. Nail clippings and hair root samples can be useful in suspected tinea unguum or tinea capitis. Most laboratories will supply appropriate specimen containers - usually small envelopes with a black interior as it is much easier to see the sample against such a background.

Skin biopsy

Biopsy may be used to provide a histopathological specimen to aid diagnosis and guide further management. Shave and punch biopsy techniques can be used. Shave excisions are less demanding technically, are useful when the lesion is small and the risk of malignancy is low. Punch biopsies remove a core of skin from the epidermis to subcutaneous fat. Ideally the biopsy should include normal skin, part of the lesion and the transition zone. Excisional biopsies aim to remove the entire lesion, with a margin dependent on the risk of malignancy. Its advantage is that the procedure can provide treatment as well as diagnosis for many lesions but it is more demanding of time, equipment and expertise.

In the Bible, the Book of Leviticus, chapter 13, deals with the question of skin disease. The first 46 verses cover the matter as delivered to Moses and Aaron and forms part of the Law of Moses. If anyone had 'sara'ath', they had to show themselves to the priest who would use certain conditions laid down in that chapter to decide if that person was ritually unclean. 'Sara'ath' probably refers to any visible form of skin disease but has been translated as 'leprosy' from the first English version of the Bible (1382 AD) to become 'malignant skin disease' in the New English Bible (1970). The term 'malignant' here should be interpreted as meaning serious, possibly contagious rather than neoplastic.

Sinister signs included if the hair near the lesion turned white and if the lesion was deeper than the surrounding skin. Sometimes a decision was delayed until after re-examination in 7 days. Verses 45 and 46 (New English Bible) state, "One who suffers from a malignant skin disease shall wear his clothes torn, leave his hair dishevelled, conceal his upper lip and cry, "Unclean, unclean." So long as the sore persists, he shall be considered ritually unclean. The man is unclean: he must live apart and shall stay outside the settlement."

Those considered to have leprosy were excluded from society and rang a bell calling, "Unclean, unclean," until well into the second millennium. Skin disease was believed to be divine retribution for sin, adding to the wretchedness of such a condition. However, many feel that those represented in our translations of the Bible as lepers did not actually have leprosy but various other skin conditions. There is no evidence for mycobacterial leprosy in Palestine and Syria at the time of Leviticus; earliest evidence for its introduction into this region dates from the time of the return of Alexander the Great's armies from India in 325-324 BC. Medical historians have proposed a range of skin conditions from Scabies¹⁷ to neurodermatitis¹⁸ as modern medical explanations of Biblical descriptions of 'Sara'ath'.