Lymphomatoid papulosis (LP) is a rare skin condition which is usually benign but can sometimes progress to a lymphoma, which is a type of cancer of the lymphatic system.

The rash usually causes small reddish spots on the skin, which tend to occur in groups. These often break down to form small ulcers. The usual pattern is that these spots will heal by themselves although this is often very slow. After a variable period of time another crop of spots will appear and the cycle begins again. There does not appear to be any way of predicting when or how often the spots will appear. The condition can appear at any age and affects both sexes equally.

For some people the treatment of LP may involve no more than careful observation. When a more active approach is needed there are a variety of treatments in use. These include radiotherapy or taking a low dose of chemotherapy (usually as a tablet). Side-effects with these treatments are uncommon. Other treatments which have been used for LP include steroid creams to the affected areas, chemotherapy creams and phototherapy (phototherapy involves taking a drug that makes the skin sensitive to the beneficial effects of ultra-violet light).

As already mentioned, LP can develop into a lymphoma or it may remain in a benign (non-cancerous) state. It tends to be a long-term, chronic, condition and it has been known for it to be up to 20 years before the cells involved become cancerous. Even so the change to a lymphoma only occurs in some patients but because of the rarity of the condition it is impossible to be precise about what percentage of people with LP will go on to develop a lymphoma.