UVA1 phototherapy is a specialized medical treatment that uses a specific range of ultraviolet A (UVA) light to address various skin conditions. This therapy involves exposing affected skin to controlled doses of UVA1 radiation within the 340-400 nanometer wavelength range. It helps manage certain dermatological disorders when other treatments, such as topical creams, have not been sufficiently effective.
Mechanism of Action
UVA1 light penetrates deeply into the skin, reaching the dermis, the layer beneath the outermost epidermis. This deep penetration allows it to interact with various cells and processes involved in skin conditions. UVA1 radiation affects immune cells, particularly T-lymphocytes, by inducing apoptosis, a form of programmed cell death, thereby reducing inflammation and immune responses in the skin.
Beyond its effects on T-cells, UVA1 also influences fibroblasts, which are cells responsible for producing collagen, and can activate matrix metalloproteinases, enzymes that break down excess collagen. This action is particularly helpful in conditions characterized by skin thickening or scarring. The therapy also has anti-inflammatory properties by modulating cytokines and chemokines, which are signaling molecules involved in inflammation. Additionally, UVA1 exposure can stimulate endothelial cells, promoting the formation of new blood vessels.
Commonly Treated Conditions
UVA1 phototherapy is used for a range of dermatological conditions, particularly those involving inflammation, fibrosis, or certain immune cell overactivity. Atopic dermatitis, a chronic inflammatory skin condition characterized by itchy, red rashes, shows improvement with UVA1 therapy due to its anti-inflammatory effects and ability to reduce symptom severity. Localized scleroderma, also known as morphea, benefits from UVA1’s ability to reduce fibrosis and inflammation, which can improve skin thickness and flexibility.
The therapy is also applied to cutaneous T-cell lymphoma, a type of non-Hodgkin lymphoma affecting the skin, where it helps induce apoptosis in cancerous T-cells. Urticaria pigmentosa, a form of mastocytosis characterized by mast cell accumulation in the skin, can improve symptoms like itching. Other conditions treated with UVA1 phototherapy include granuloma annulare, causing ring-shaped lesions, and extragenital lichen sclerosus, a chronic inflammatory skin condition. UVA1 can also be used for conditions resistant to other phototherapy methods, such as certain cases of psoriasis or sarcoidosis.
Treatment Procedure
A UVA1 phototherapy session involves the patient standing or lying down in a specialized cabinet equipped with UVA1 lamps. Before treatment, patients are asked to remove clothing from the areas to be treated, and protective goggles are provided for eye protection. Men may also be advised to wear dark underwear or cover their genitalia for protection.
Sessions are brief, often lasting a few minutes, though they can extend up to 45 minutes depending on the individual’s skin type and prescribed dose. Treatment courses involve sessions 2-5 times per week for several weeks, often ranging from 3 to 12 weeks, with the total number of sessions varying based on the condition and response. Dosing regimens can be categorized as low (10-20 J/cm²), medium (50-60 J/cm²), or high (130 J/cm²) dose per session, chosen based on the skin condition and patient tolerance.
Potential Side Effects and Precautions
UVA1 phototherapy has a favorable side effect profile compared to some other light therapies, but patients may experience acute and chronic effects. Common short-term side effects include temporary skin redness (erythema) appearing within hours and lasting up to 48 hours, skin dryness, itching, and increased pigmentation or tanning. Some individuals may also experience a reactivation of herpes simplex (cold sores) or develop a polymorphous light eruption.
Long-term risks associated with UVA1 phototherapy include premature skin aging (photoaging). The evidence for UVA1 directly contributing to skin cancer risk is under study, but patients who have received numerous treatments or have a history of other phototherapies should undergo regular skin cancer screenings. Patients should avoid sunbathing or using sunbeds during treatment and apply broad-spectrum sunscreen with an SPF of 50 and a UVA 5-star rating after sessions, avoiding application before treatment as it might hinder absorption. It is also important to inform healthcare providers about all medications, including over-the-counter drugs and supplements, as some can increase photosensitivity.