Alitretinoin, an active substance with therapeutic effects on eczema?

Naturally present in the human body, alitretinoin is a hormone related to vitamin A capable of binding to all known subtypes of retinoic acid receptors, namely RAR-α, RAR-β, RAR-ɣ, RXR-α, RXR-β and RXR-ɣ, unlike other retinoids which are specific agonists to RAR or RXR receptors. Once these receptors are activated by binding with alitretinoin, they behave as transcription factors that regulate the expression of certain genes, particularly those controlling the processes of cell differentiation and proliferation and angiogenesis, that is, the formation of new blood vessels.

Furthermore, alitretinoin has immunomodulatory and anti-inflammatory effects that are beneficial in combating eczema. It notably aids in regulating inflammation in eczema by reducing the expression of certain molecules involved in the immune response, such as CXCR3 ligands and the chemokine CCL20, which are overexpressed in skin lesions. Alitretinoin acts by moderating their production in keratinocytes exposed to cytokines and in the dermal endothelial cells. Moreover, this compound limits the activation and proliferation of leukocyte subsets stimulated by cytokines, as well as antigen-presenting cells, thus helping to decrease the inflammatory response.

Alitretinoin is available in the form of capsules to be swallowed. The treatment typically starts with a dose of 30 mg per day, after which the dosage is adjusted between 10 and 30 mg per day based on tolerance and effectiveness, for a duration of 12 to 24 weeks.

Alitretinoin is a molecule that has been the subject of numerous clinical studies, demonstrating its effectiveness in managing hand eczema. Here are a few examples:

Like any medication, alitretinoin is associated with risks and usage precautions. It is first important to note that this medication is strictly contraindicated in pregnant women or those who could become pregnant if they do not follow a strict pregnancy prevention programme. Due to its high teratogenic potential, contraception must be implemented before, during and up to one month after stopping the treatment. Regular pregnancy tests are also required and breastfeeding is prohibited during the treatment, due to the risk of alitretinoin passing into breast milk.

Another contraindication: alitretinoin should not be prescribed in cases of severe hepatic or renal insufficiency, hypercholesterolemia, as this substance tends to increase LDL levels, or hypervitaminosis A. It is also associated with an increased risk of psychiatric disorders, particularly depression, hence the importance of closely monitoring the patient's psychological state, especially in individuals with a history of mood disorders. Other notable side effects include musculoskeletal damage, significant skin and lip dryness, as well as a risk of photosensitivity requiring avoidance of excessive sun exposure and proper protection.

In the event of a severe reaction, such as pancreatitis, an inflammatory bowel disease, a persistent increase in transaminases, or symptoms of intracranial hypertension, it is necessary to discontinue the treatment.