Differential diagnoses: Skin lesions

Dr Nigel Stollery explains how to differentiate four similar-looking superficial skin lesions.

Superficial basal cell carcinoma

Presentation

  • Superficial basal cell carcinoma (BCC) is usually a solitary lesion, which grows slowly
  • Occurs on sun-exposed areas, such as the trunk and lower legs
  • No response to topical steroids or antifungals
  • There is usually no associated itch or pain

Management

  • If the diagnosis is unsure, a punch biopsy can be useful
  • Without treatment, lesions may progress to a nodular BCC
  • Topical treatments such as imiquimod or 5-fluorouracil can be used
  • Other treatments include formal excision
  • Advice on sun care is important

Bowen's disease

Presentation

  • More than one lesion may be present in a similar area
  • More common on sun-exposed areas such as the trunk and lower legs
  • Slow increase in size is common
  • There is usually no associated itch or pain

Management

  • If the diagnosis is unsure, a punch biopsy can be useful
  • Untreated, 2-3% may progress to squamous cell carcinoma (SCC)
  • Topical treatments such as imiquimod or 5-fluorouracil can be used
  • Other treatments include formal excision or cryotherapy
  • Advice on sun care is important

Psoriasis

Presentation

  • Widespread disease common over the extensor surfaces of elbows and knees
  • The nails and scalp may also be affected
  • Plaques associated with thick silvery-white scale and well demarcated edges
  • Five per cent of patients may also have psoriatic arthropathy
  • Other family members may be affected by the condition

Management

  • Psoriasis may respond to treatment, but relapses are common over many years
  • Currently there is no known cure for the condition
  • Treatments include emollients and vitamin D analogues, used alone and in combination with topical steroids
  • Light or oral treatments useful in resistant or widespread disease
  • Biologics work very well in severe disease

Actinic keratosis

Presentation

  • Lesions occur as a result of chronic sun damage and are common on the head and hands
  • Incidence increases with age
  • Usually multiple grey, rough, scaly macules or papules, rarely greater than 1cm in diameter
  • Transition to SCC may rarely occur and should be considered in lesions that do not respond to treatment
  • The diagnosis is usually clinical, unless SCC is suspected, when a punch biopsy can be useful

Management

  • Education is essential to prevent further damage
  • Topical treatments such as 5-fluorouracil are very effective
  • New treatments include ingenol mebutate, which only requires three days of treatment
  • Cryotherapy can be useful
  • For larger, very thickened lesions, curettage and cautery can be effective

For more clinical images to compare and diagnose, click here

  • Dr Stollery is a GPSI in dermatology in Kibworth, Leicestershire

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