Cutaneous horns, also known by the Latin name cornu cutaneum, are unusual keratinous skin tumors with the appearance of horns, or sometimes of wood or coral. Formally, this is a clinical diagnosis for a "conical projection above the surface of the skin." They are usually small and localized but can, in very rare cases, be much larger. Although often benign, they can also be malignant or premalignant. Signs and symptoms
The lesion at the base of the keratin mound is benign in the majority of cases. Malignancy is present in up to 20% of cases, with squamous-cell carcinoma being the most common type. The incidence of squamous-cell carcinoma increases to 37% when the cutaneous horn is present on the penis. Tenderness at the base of the lesion often suggests the presence of a possible underlying squamous-cell carcinoma. Cause
The cause of cutaneous horns is still unknown, but it is believed that exposure to radiation can trigger the condition. This is evidenced by a higher rate of cases occurring on the face and hands, areas that are often exposed to sunlight. Other cases have reported cutaneous horns arising from burn scars. As with many other wart-like skin conditions, a link to the HPV virus family, especially the HPV-2 subtype has been suggested. Diagnosis
Cutaneous horn usually arises due to an underlying epidermal lesion, the most common being verruca vulgaris (wart), actinic keratosis (a potentially pre-malignant lesion of dysplastic keratinocytes), or squamous cell carcinoma (a form of skin cancer). These can look essentially identical clinically.
Difelikefalin, sold under the brand name Korsuva, is an analgesic opioid peptide used for the treatment of moderate to severe itching. It acts as a peripherally specific, highly selective agonist of the κ-opioid receptor (KOR).Difelikefalin was approved for medical use in the United States in August 2021.Difelikefalin acts as an analgesic by activating KORs on peripheral nerve terminals and KORs expressed by certain immune system cells. Activation of KORs on peripheral nerve terminals results in the inhibition of ion channels responsible for afferent nerve activity, causing reduced transmission of pain signals, while activation of KORs expressed by immune system cells results in reduced release of proinflammatory, nerve-sensitizing mediators (e.g., prostaglandins). Society and culture
Legal status
On 24 February 2022, the Committee for Medicinal Products for Human Use (CHMP) of the European Medicines Agency adopted a positive opinion, recommending the granting of a marketing authorization for the medicinal product Kapruvia, intended for treatment of moderate-to-severe pruritus associated with chronic kidney disease. The applicant for this medicinal product is Vifor Fresenius Medical Care Renal Pharma France. Difelikefalin was approved for medical use in the European Union in April 2022. Research
It is under development by Cara Therapeutics as an intravenous agent for the treatment of postoperative pain. An oral formulation has also been developed. Due to its peripheral selectivity, difelikefalin lacks the central side effects like sedation, dysphoria, and hallucinations of previous KOR-acting analgesics such as pentazocine and phenazocine. In addition to use as an analgesic, difelikefalin is also being investigated for the treatment of pruritus (itching).