Dermatology Case Studies

Clinical Assessment of a Lesion

He has attached a photograph of the toe:

Figure 10: Brown mark under big toe nail, with radiating borders

You assess this photograph according to the ABCDE criteria, a very useful system for examining most skin lesions
You might have to modify your approach a little in this case
It is important to note that this photograph shows varying discoloration on/beneath the toe nail
It is also noteworthy that the bruising does not extend to the nail bed, a feature which should raise suspicion here
It also does not look like a bruise

Click each of letters of the mnemonic to reveal the assessment:

A is for Asymmetry

In this case the shape of the lesion is not consistent with bruising, or with blood trapped beneath the nail; this is concerning

B is for Border irregularity

Again, this is an unusual looking discoloured lesion in/beneath the toenail; this is concerning
Subungual melanomas can take various forms ranging from a coloured banding in the nail, a lump papilloma or verruca-type lesion in or around the nail
Any nail changes which are not obviously bruising or fungal infection should probably be assessed by a specialist

C is for Colour variability and/or Changing colour

This photograph shows variegated brown colouration beneath/below the nail
It looks quite different to the bruising commonly seen. It is an unusual appearance and in the absence of any history of trauma is concerning
Subungual melanomas can take various forms ranging from, discoloration beneath the nail, coloured banding in the nail, a lump papilloma or verruca-type lesion in or around the nail
Any unusual nail changes, in the absence of a history of trauma, should be assessed by a skin specialist

D is for Different

The photograph shows unusual discoloration beneath the nail; there is no history of trauma
Subungual melanomas can take various forms ranging from, discoloration beneath the nail, coloured banding in the nail, a lump papilloma or verucca-type lesion in or around the nail
Any unusual nail changes, in the absence of a history of trauma, should be assessed by a skin specialist

E is for Evolving (changing)

The patient reports that the discoloration is changing and developing
This is a concerning feature in this case and this patient requires careful assessment by a skin specialist