Differential diagnoses - Tinea, BCC, herald patch and fixed drug eruption

Dr Nigel Stollery explains how to recognise basal cell carcinoma among four similar lesions.

Fixed drug eruption

Presentation

  • Reaction to particular medication which recurs every time the medication is taken
  • With continued exposure, multiple sites may be affected
  • Aetiology not fully understood
  • Well-defined round or oval patches of redness and swelling
  • Lesions develop 30 minutes to eight hours after taking the drug
  • Common causes include paracetamol, tetracyclines and NSAIDs

Management

  • Lesions are self-limiting
  • Postinflammatory hyperpigmentation may occur
  • Future avoidance of causative drugs is recommended

Herald patch

Presentation

  • Single lesion initially, followed by multiple smaller lesions
  • Called the herald patch because it heralds the development of pityriasis rosea
  • Occurs more commonly on the trunk
  • Has a fine surface scale and may be itchy
  • More common in autumn/winter

Management

  • Self-limiting condition that usually settles after six to eight weeks
  • Topical antipruritics, such as calamine, may help the itch
  • In severe or widespread cases, moderately potent topical steroids may be helpful

Tinea

Presentation

  • Fungal infection more commonly referred to as ringworm
  • Affects all age groups
  • Expands with time, with central clearance
  • Usually very itchy, solitary lesion
  • Occurs anywhere on the body

Management

  • Treatment includes topical or oral antifungals

Nodular basal cell carcinoma

Presentation

  • The most common form of skin cancer
  • Incidence increases with age
  • More common on areas with higher UV light exposure
  • Very low metastatic potential
  • Untreated lesions can progress and become very extensive
  • Multiple lesions are common

Management

  • Main treatment is surgical excision with Mohs micrographic surgery for more difficult lesions
  • Radiotherapy may be an option for the elderly or for those with extensive lesions
  • Dr Stollery is a GP in Kibworth, Leicestershire

Click here to take a test on this article and claim a certificate on MIMS Learning

Have you registered with us yet?

Register now to enjoy more articles and free email bulletins

Register

Already registered?

Sign in

Follow Us:

Just published

UK COVID-19 alert level raised as GPs prioritised for testing

UK COVID-19 alert level raised as GPs prioritised for testing

The government has raised the UK's COVID-19 alert level to four amid reports that...

UK on course for 50,000 COVID-19 cases a day by mid-October

UK on course for 50,000 COVID-19 cases a day by mid-October

The UK could see 50,000 COVID-19 cases per day by mid-October, with the epidemic...

Stricter short-term COVID-19 measures needed to avoid second national lockdown, BMA warns

Stricter short-term COVID-19 measures needed to avoid second national lockdown, BMA warns

COVID-19 infection rates will ‘soar’ and the NHS will ‘once again be crippled’ if...

Practices handed one-month opt-out window as revamped network DES unveiled

Practices handed one-month opt-out window as revamped network DES unveiled

NHS England has unveiled a revamped DES package for 2020/21 confirming new targets,...

GPs delivered huge rise in face-to-face consultations in week before NHS England letter

GPs delivered huge rise in face-to-face consultations in week before NHS England letter

GPs delivered a huge increase in face-to-face appointments in the week before NHS...

RCGP facing legal action over stance on assisted dying

RCGP facing legal action over stance on assisted dying

The RCGP is facing legal action over its decision to remain opposed to assisted dying...