Phototherapy And Photodiagnostic Methods For The Practitioner

Wei Sheng Chong, Jiun Yit Pan;Sern Ting Eugene Tan

• Publisher: WSPC
• Year: 2017
• ISBN:
  9789813146655
• Topic: Medicine
• Subtopic: Dermatology

Phototherapy, or the usage of light to treat diseases, is an important modality in a physician's therapeutic armamentarium. It is effective for a number of common skin conditions like atopic dermatitis, psoriasis and vitiligo. The accurate diagnosis of a photodermatosis or light-related skin disorder relies on a good clinical history and physical examination, supported by diagnostic investigations such as phototesting.

Phototherapy and Photodiagnostic Methods for the Practitioner is the first published set of practical guidelines for Asian skin, drawing upon our cumulative clinical experience with phototherapy for various conditions at the National Skin Centre in Singapore, amalgamated with up-to-date evidence from the scientific literature. It is designed to serve as a concise and comprehensive reference manual for dermatologists, as well as clinicians, medical physicists and nurses with an interest in photodiagnostic investigations and phototherapy for the evaluation and treatment of skin disorders.

Contents: Introduction to Phototherapy;Nursing Considerations in Phototherapy;Narrowband Ultraviolet B Phototherapy;Combined Ultraviolet A/Narrowband Ultraviolet B Phototherapy;Psoralen-Ultraviolet A Photochemotherapy;Ultraviolet A-1 Phototherapy;Excimer Light Phototherapy;Photodynamic Therapy;Phototesting;Photopatch Testing;Photoprovocation Testing;Minimal Erythema Dose Testing Dosimetry;Minimal Phototoxic Dose Testing Dosimetry;Photopatch Testing Series;Evidence Grading for Recommendations;
Readership: Medical Technicians, Dermatology Residents and Trainees, Medical Doctors, Nurses, Photobiologists, Dermatologists, General Practitioners, and Medical Physicists.
Phototherapy, Photodiagnostic Methods, Skin, Dermatology, Light, Light, Lasers, Asian Skin0

Chapter

1

Introduction to Phototherapy

•Phototherapy and photochemotherapy are established modalities of treatment for a variety of skin diseases, including atopic dermatitis, psoriasis, vitiligo and mycosis fungoides.

•The therapeutic effect is based on the interaction between ultraviolet radiation (UVR) and the skin, and is believed to be via the induction of immunosuppression and T-cell apoptosis, leading to cell-cycle arrest in hyperproliferating cells such as the keratinocytes.

•Phototherapy is the therapeutic use of UVR without the use of an exogenous photosensitiser.

•Photochemotherapy (psoralen with ultraviolet A or PUVA) involves the combined use of the drug psoralen with ultraviolet A (UVA) radiation. Psoralen, given topically or orally, acts as a photosensitiser to enhance the effect of UVA.

Chapter

2

Nursing Considerations in Phototherapy

Pre-Phototherapy Advice

•The patient should be advised that multiple sessions of phototherapy would be required before clinical improvement is seen. For instance, an average of 20 to 25 sessions of narrowband ultraviolet B (NBUVB) phototherapy is required for effective treatment of psoriasis. Regular irradiation of up to three times a week is required, especially in the initial clearing phase of treatment. The patient should also be advised that irregular treatments may affect and delay a successful outcome.

•The first exposure is usually short, lasting seconds to a minute, depending on the person’s Fitzpatrick skin phototype.

•The objective is to apply the largest phototherapy dose that causes mild, asymptomatic erythema. Once this is reached, further doses will be adjusted to maintain this mild, asymptomatic erythema.

•Once the patient is lesion-free, the maintenance phase with reduction in frequency of treatment will commence.

•Applying an emollient such as liquid paraffin on the skin before irradiation increases UVR permeability and hence the therapeutic effect, especially in the context of psoriasis treatment. However, the use of extremely greasy and opaque ointments may impede UVR permeability.

NBUVB Treatment Procedure

Pre-NBUVB Irradiation

1.Explain the treatment procedure and side effects of NBUVB phototherapy, and obtain informed consent.

2.A shower prior to NBUVB phototherapy can aid in reducing skin scaling, especially in psoriasis.

3.Prior to irradiation, assess the skin condition for

a.Extent and severity of involvement.

b.Response of lesional and non-lesional skin to previous treatment.

During NBUVB Irradiation

1.A thin layer of liquid paraffin is applied to the scaly lesions to help in enhancing NBUVB penetration and its therapeutic effect.

2.Ensure that the male patient wears protective gear to cover the genital area.

3.The patient and nurse must wear UV-protective goggles.

4.Protect the patient’s face with a covering hood, unless the face requires irradiation. For patients with long hair, tie the hair above the neck at all times during each treatment session.

5.An additional hand-held safety timer will be set for each treatment session, corresponding to the time calculated for the NBUVB dose for that treatment.

Post-NBUVB Treatment Advice

1.Warn the patient that erythema and mild skin discomfort may appear after treatment. Such effects are easily relieved by a cold shower and the application of a cold moisturiser. However, if more severe reactions such as pain, swelling and blistering develop, the patient should be advised to consult the doctor immediately.

2.Minimise further exposure to natural UVR from the sun by wearing a long-sleeved shirt with long pants or carrying an umbrella when going outdoors, and by applying a sunscreen.

3.Continue the usual topical treatment as prescribed.

4.Record the dose and the time of NBUVB delivered, and the progress of the patient’s condition.

Oral PUVA Treatment Procedure

Pre-UVA Irradiation

1.Explain the treatment procedure and side effects of PUVA photochemotherapy, and obtain informed consent.

2.A shower prior to PUVA photochemotherapy can aid in reducing skin scaling, especially in psoriasis.

3.Ensure that the patient has taken the prescribed dose of 8-methoxypsoralen (8-MOP) tablets (Meladinine^®, CLS Pharma) two hours before the scheduled treatment time. This serves to increase the sensitivity of the skin to UVA radiation. The effect of the medication peaks approximately two hours after oral ingestion.

4.Prior to irradiation, assess the skin condition for

a.Extent and severity of involvement.

b.Response of lesional and non-lesional skin to previous treatment.

During UVA Irradiation

1.A thin layer of liquid paraffin is applied to the scaly lesions to help in enhancing UVA penetration and its therapeutic effect.

2.Ensure that the male patient wears protective gear to cover the genital area.

3.The patient and nurse must wear UV-protective goggles.

4.Protect the patient’s face with a covering hood, unless the face requires irradiation. For patients with long hair, tie the hair above the neck at all times during each treatment session.

5.An additional hand-held safety timer will be set for each treatment session, corresponding to the time calculated for the UVA dose for that treatment.

Post-PUVA Treatment Advice

1.Warn the patient that erythema and mild skin discomfort may appear after treatment. Such effects are easily relieved by a cold shower and the application of a cold moisturiser. However, if more severe reactions such as pain, swelling and blistering develop, the patient should be advised to consult the doctor immediately.

2.Minimise further exposure to natural UVR from the sun by wearing UV-protective sunglasses (must be worn for 24 hours after ingestion of oral 8-MOP) and a long-sleeved shirt with long pants, or carrying an umbrella when going outdoors, and by applying a sunscreen.

3.Continue the usual topical treatment as prescribed.

4.Record the dose and the time of UVA delivered, and the progress of the patient’s condition.

Bath/Soak/Paint PUVA Treatment Procedure

There are a few differences between bath/soak/paint and oral PUVA photochemotherapies:

•Instead of ingesting 8-MOP tablets, in bath PUVA photochemotherapy, the patient is bathed in warm water with 8-MOP solution added to a final concentration of 3.75 mg/L at 37°C.

•In soak PUVA photochemotherapy, the patient’s hands and/or feet are soaked in water with 8-MOP solution added to a final concentration of 3.75 mg/L.

•In paint PUVA photochemotherapy, 8-MOP solution is applied as a thin layer with a cotton swab to lesional skin, taking care to avoid applying to surrounding unaffected skin.

•In bath and soak PUVA photochemotherapies, the patient is soaked for 20 minutes. Keep the water circulating to maintain homogeneous concentration of the diluted 8-MOP. Subsequently, the patient is exposed to UVA radiation immediately, or within 15 minutes.

•In paint PUVA photochemotherapy, after applying the 8-MOP solution to the lesional skin, wait for a further 20 minutes before UVA irradiation.

•After UVA irradiation, the patient must thoroughly wash off any remaining 8-MOP that is left on the skin.

•There is ...