Question: What is (are) Pityriasis rubra pilaris ?
Answer: Pityriasis rubra pilaris (PRP) refers to a group of skin conditions that cause constant inflammation and scaling of the skin. Affected people have reddish-orange colored patches; they may occur everywhere on the body or only on certain areas. There are several types of PRP, which are classified based on age of onset, body areas affected, and whether other associated conditions are present. PRP is usually sporadic (occurring randomly) but some forms may be inherited.
Source: GARD

Question: What causes Pityriasis rubra pilaris ?
Answer: What causes pityriasis rubra pilaris? In most cases, pityriasis rubra pilaris (PRP) occurs sporadically for unknown reasons. In a few families with the inherited form, familial PRP, the condition is caused by mutations in the CARD14 gene. This gene gives instructions for making a protein that turns on other proteins that regulate genes that control the body's immune responses and inflammatory reactions. It also protects cells from certain signals that would otherwise cause them to self-destruct. The CARD14 protein is particularly abundant in the skin. Mutations in the gene can cause a person to have an abnormal inflammatory response. Researchers are trying to find out how these mutations cause the specific features of familial PRP.
Source: GARD

Question: What are the treatments for Pityriasis rubra pilaris ?
Answer: How might pityriasis rubra pilaris be treated? Treatment of pityriasis rubra pilaris (PRP) is mainly based on reports of patients' experiences. No controlled trials have been done, so the effectiveness and safety of treatments is unclear. Currently there are no treatments approved by the US Food and Drug Administration (FDA) or the European Medicines Agency (EMA) for use in PRP. Management of PRP often involves systemic and topical therapies combined. Topical therapies can help with the symptoms and may be enough for people with mild PRP. Topical treatments are usually combined with systemic therapy for PRP that affects a large part of the body. Most people need systemic therapy to control the condition. Oral retinoids (synthetic vitamin A derivatives) are usually preferred as a first-line systemic treatment for PRP. Methotrexate may be an alternative option for people who should not use systemic retinoids, or who don't respond to systemic retinoid therapy. For people who don't respond well to retinoid or methotrexate therapy, options may include biologic TNF-alpha inhibitors, azathioprine, cyclosporine, and/or phototherapy. Topical treatments used for PRP may include topical corticosteroids, keratolytics, tar, calcipotriol, topical tretinoin, and tazarotene. Some of the medications used to treat PRP can harm a developing fetus and are not recommended for use right before or during pregnancy. People seeking information about specific treatment options for themselves or family members should speak with their health care provider.
Source: GARD