LPLK can be thought of as a ‘regressing’ Seb K or solar lentigo. So you first need to know what a Seb K or Solar Lentio looks like. In the inflammatory phase, LPLK is usually somewhat pink or red. In the ‘burnt-out’ phase, LPLK is typically grey or greyish-brown.
The term “lichenoid reaction” is often used by the pathologist. The pathology will determine whether the LPLK has derived from a solar lentigo or seborrhoeic keratosis.
LPLK tends to be identified at a skin check for one of two reasons
- A Seborrhoeic keratosis or age spot has developed a lichenoid reaction. It’s usually possible to identify the lesion as ‘having been’ a Seb K or age spot, and to identify changes of LPLK on dermoscopy.
- Longstanding LPLK is a <1cm patch of pale grey colour skin. The diagnosis is normally confirmed with dermoscopy.
LPLK may look similar to skin cancers such as IEC and lentigo maligna.