Phototherapy consists of the delivery of light or ultraviolet radiation to treat various, autoimmune diseases of the skin such as psoriasis and vitiligo. This field has seen several major advances over the years, the most recent being targeted phototherapy
Targeted phototherapy, also called concentrated phototherapy, focused phototherapy and microphototherapy, involves delivery of ultraviolet radiation directly focused on, or targeted at, the skin lesion through special delivery mechanisms.
Advantages of targeted phototherapy over conventional phototherapy
Several advantages have been claimed for targeted phototherapy.
- • Exposure of involved areas only and sparing of uninvolved areas, thus minimizing acute side effects such as erythema (sunburn) and long-term risk of skin cancer in unaffected skin.
- • Quick delivery of high-doses of energy and short treatment sessions.
- • Less frequent and less numerous visits to clinic, reducing patient inconvenience.. The treatment can be administered twice aweek or even once a week and each treatment session lasts for seconds only.
- • Allows treatment of difficult areas such as scalp, nose, genitals, oral mucosa and ears.
- • Easy administration for children. Children are intimidated by large machines used in conventional phototherapy.
Indications for targeted phototherapy
- • “The EXCIMER 308 SYSTEM has revolutionized the therapy of pruritic, inflammable skin diseases! It is highly effective for all the indications and achieves fast, long lasting results.”
- • The ideal indications are persistent, localized lesions.
- • Targeted NBUVB phototherapy is an effective treatment option in localized vitiligo with a rapid onset of repigmentation seen as early as 2 nd week of treatment. It can be combined with systemic therapies if needed. Best response is seen on the face and neck areas.
Examples of skin conditions that may be treated by targeted phototherapy include:
- • psoriasis
- • scalp psoriasis
- • seborrhoeic dermatitis
- • vitiligo
- • Alopecia areata
- • cutaneous T-cell Lymphoma (mycosis fungoides)
- • atopic dermatitis
- • pityriasis lichenoides
- • urticaria pigmentosa
- • morphoea
- • scleroderma
- • hand dermatitis
Mechanism of action
Most targeted phototherapy devices emit radiation in the UVB range, with peak emission in the narrowband wavelength (around 308-311 nm).
The following mechanisms have been proposed to explain UV's efficacy in the treatment of skin diseases:
- • Apoptosis of pathogenically relevant cells including T-cell apoptosis in the treatment of psoriasis, mycosis fungoides and atopic dermatitis, and mast cell apoptosis in pruritic skin disorders.
- • Stimulation of melanocyte-stimulating hormone, increased melanocyte proliferation, and melanogenesis as in vitiligo.
- • Decreased release of histamine from both basophils and mast cells in histaminic disorders such as urticaria pigmentosa.
- • UVB radiation has an immune modeling effect which can normalize pathologically altered cellular activities.
Safety of targeted phototherapy
Adverse effects to the treatment are uncommon.Ultraviolet radiation exposure leads to skin ageing and skin cancer. The risks are lower when limited skin is exposed to it, as is the case with
- • UVB may cause acute phototoxicity (like sunburn), with redness and blistering, beginning in the first 4–6 hours after exposure and peaking at 12–24 hours.
- • Male genitalia should be shielded during every treatment session as they are particularly sensitive to the development of skin cancers.