Assessment Of Skin Rash Flashcards
What do you ask before considering the lesion in a patient presenting with a rash?
Basic demographics:
- Age - infectious diseases are more common in children but malignancy gets more common with advancing age.
- Sex - some conditions are more common in men or more common in women.
- Race and country of origin.
- Current residence - important in an infectious outbreak.
Which questions should you ask about a lesion?
Duration Location Provoking or relieving factors. Associated symptoms Response to treatment
Which questions do you ask about the duration of the lesion?
Onset - sudden versus gradual. Establish whether this is an acute presentation or an ongoing chronic problem.
Previous episodes – e.g., photodermatoses tend to recur every spring with the onset of good weather.
Change - fluctuation versus persistence. Consider variation in severity – e.g., occupational contact allergic dermatitis may improve when on holiday. Urticaria may be quite dynamic in its presentation but others are much more static
Which questions do you ask about the location of the lesion?
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 in sun-exposed areas.
Establish whether the lesion has spread.
Which questions do you ask about provoking or relieving factors of a lesion?
Heat and cold may be either aggravating or relieving factors, especially with urticaria;
repeated drug exposures with fixed drug eruptions.
What are the associated symptoms of lesions to ask about?
Itch - 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.
Tenderness - inflammation is often tender.
Bleeding or discharge - bleeding may indicate malignancy and discharge may occur with an infected lesion.
Systemic symptoms - such as pyrexia, malaise, joint pain and swelling or weight loss. Some skin lesions are markers for underlying malignancy.
Why do you ask about response to treatment of a lesion?
A number of treatments may have been tried prior to consultation - eg, antiseptic lotions, calamine, antihistamines, (OTC) steroid or antifungal creams, herbal remedies or medication prescribed for another family member or friend.
Complementary medicines such as Chinese herbs may have unknown ingredients and potency.
Partially treated lesions are the most difficult to diagnose.
Which past medical history are important in relation to a lesion?
Bowen’s syndrome
Diabetes may suggest necrobiosis lipoidica
Previous skin cancer
History of atopy for eczema
Why do you ask about family history when assessing a rash/lesion?
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.
Familial atypical mole and melanoma (FAMM) syndrome should be considered where several family members have multiple melanocytic lesions, some atypical, with at least one case of melanoma in the family.
Why do you ask about drug history when assessing a rash/lesion?
Prescribed, over the counter or other therapies.
Drug eruptions can be highly variable. Illegal drug use may have dermatological manifestations – e.g., anabolic steroids and acne.
Immunosuppression and skin cancer
New changes to medications
Why do you ask about social history when assessing a rash/lesion?
Occupation, hobbies and pastimes:
o where there may be exposure to chemicals or a very hot environment, for example.
Travel:
o Particularly to exotic locations, may increase the risk of rarer tropical diseases.
o Consider cumulative exposure to sunlight or sunbeds and history of sunburn, as these increase the risk of skin malignancies.
o Alcohol use has an association with psoriasis.
o Smoking increases the risk of some malignancies and has a close association with palmoplantar pustular psoriasis.
Why should you ask about the psychological effects of having skin conditions?
People with severe, chronic, visible and disfiguring skin disease may suffer from anxiety, depression and social isolation; these issues require exploration.
Psychological problems may also cause skin disease- e.g. dermatitis artefacta.
What are the investigations that can be done when assessing a skin rash/lesion?
Swabs for bacteriology and virology.
Skin scrapings and nail clippings for microscopy to diagnose fungal infections, pityriasis versicolor and ectoparasitic infections such as scabies.
Hair root samples can be useful in suspected tinea capitis.
Wood’s light
Skin biopsy- shave and punch biopsies can be used.
Patch and skin prick tests for contact allergy dermatitis and other allergies.
What is wood’s light?
This 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.
Erythrasma due to Corynebacterium minutissimum fluoresces a bright coral red.
Tinea capitis caused by Microsporum canis and Microsporum audouinii fluoresces a light bright green but most tinea capitis infections are caused by Trichophyton species that do not fluoresce.
P. aeruginosa, especially in burns, may provide 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 (cholasma).
What are punch biopsies?
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.
