Phototherapy Health Dictionary

A potentially serious disease of the newborn, characterised by haemolytic ANAEMIA (excessive destruction of red blood cells) and JAUNDICE. If severe, it may be obvious before birth because the baby becomes very oedematous (see OEDEMA) and develops heart failure – so-called hydrops fetalis. It may ?rst present on the ?rst day of life as jaundice and anaemia. The disease is due to blood-group incompatibility between the mother and baby, the commoneset being rhesus incompatibility (see BLOOD GROUPS). In this condition a rhesus-negative mother has been previously sensitised to produce rhesus antibodies, either by the delivery of a rhesus-positive baby, a miscarriage or a mismatched blood transfusion. These antibodies cross over into the fetal circulation and attack red blood cells which cause HAEMOLYSIS.

Treatment In severely affected fetuses, a fetal blood transfusion may be required and/or the baby may be delivered early for further treatment. Mild cases may need observation only, or the reduction of jaundice by phototherapy alone (treatment with light, involving the use of sunlight, non-visible ULTRAVIOLET light, visible blue light, or LASER).

Whatever the case, the infant’s serum BILIRUBIN – the bilirubin present in the blood – and its HAEMOGLOBIN concentration are plotted regularly so that treatment can be given before levels likely to cause brain damage occur. Safe bilirubin concentrations depend on the maturity and age of the baby, so reference charts are used.

High bilirubin concentrations may be treated with phototherapy; extra ?uid is given to prevent dehydration and to improve bilirubin excretion by shortening the gut transit time. Severe jaundice and anaemia may require exchange TRANSFUSION by removing the baby’s blood (usually 10 millilitres at a time) and replacing it with rhesus-negative fresh bank blood. Haemolytic disease of the newborn secondary to rhesus incompatibility has become less common since the introduction of anti-D (Rho) immunoglobulin. This antibody should be given to all rhesus-negative women at any risk of a fetomaternal transfusion, to prevent them from mounting an antibody response. Anti-D is given routinely to rhesus-negative mothers after the birth of a rhesus-positive baby, but doctors should also give it after threatened abortions, antepartum haemorrhages, miscarriages, and terminations of pregnancy.

Occasionally haemolytic disease is caused by ABO incompatibility or that of rarer blood groups.... haemolytic disease of the newborn

A common disorder of skin pigmentation in which patches of skin, most commonly on the face, hands, armpits, and groin, lose their colour. Vitiligo is thought to be an autoimmune disorder. It may occur at any age but usually develops in early adulthood.

Spontaneous repigmentation occurs in some cases.

A course of phototherapy using PUVA can also induce repigmentation of the skin, and creams containing corticosteroid drugs may help.... vitiligo

This chronic, relapsing in?ammatory skin disease is extremely common, affecting about 2 per cent of the UK population. Frequently it is mild and trivial, affecting only the points of the elbows or knees and the scalp, but in a substantial minority of sufferers the disease is much more widespread and causes considerable discomfort and social embarrassment. Rarely, it can be universal and even life-threatening.

The predisposition to psoriasis is genetic, multiple genes being involved, but postnatal factors such as acute infection, hormonal disturbance, pregnancy and drugs can in?uence or provoke it. The sexes are equally affected and onset is most common in the second or third decade of life.

The psoriatic lesion is dull red, scaly and well de?ned. Scale is shed constantly, either in tiny pieces or as large plaques. The scalp is usually affected but the disease does not cause signi?cant hair loss. The ?ngernails may be pitted or ridged and the toenails grossly thickened. Several clinical patterns occur: in guttate psoriasis, a sudden explosion of multiple tiny lesions may follow a streptococcal throat infection, especially in children. Larger lesions are characteristic of discoid (plaque) psoriasis, the usual adult form. In the elderly the plaques may be mainly in the large body folds – ?exural psoriasis. Rarely, psoriasis may be universal (psoriatic erythroderma), or a sterile pustular eruption may supervene (pustular psoriasis).

Mucous membranes in the mouth and elsewhere are not affected. Psoriasis does not affect internal organs, but in about 1 per cent of subjects an in?ammatory joint disease (psoriatic arthritis) may be associated with the condition.

Treatment There is no absolute cure, but several agents used topically are of value including coal-tar extracts, DITHRANOL, CORTICOSTEROIDS and synthetic derivatives of vitamins A and D. Ultraviolet B phototherapy (and natural sunlight) bene?ts most but not all psoriatics. Systemic therapy, including PHOTOCHEMOTHERAPY, is reserved for severe forms of psoriasis. METHOTREXATE, CICLOSPORIN A and oral RETINOIDS are the most e?ective drugs, but they are potentially dangerous and require expert monitoring.

Patient information may be obtained through the Psoriasis Association.... psoriasis

A drug that is used in the treatment of psoriasis. Dithranol is prescribed as an ointment, paste, or cream and works by slowing the rate at which skin cells multiply. This effect can be boosted by ultraviolet light treatment (see phototherapy). Dithranol can cause skin inflammation.... dithranol

A form of phototherapy involving exposure to sunlight.... heliotherapy

A length of thread or other material used for ligation.lightening A feeling experienced by many pregnant women when the baby’s head descends into the pelvic cavity. Lightening usually occurs in the final 3 weeks of pregnancy, leaving more space in the upper abdomen and relieving pressure under the diaphragm. light treatment See phototherapy. lignocaine Former name for lidocaine. limb, artificial An artificial leg or arm, known medically as a prosthesis, which is fitted to replace a limb that has been missing from birth or lost as a result of amputation (see limb defects).... ligature

A type of phototherapy used to treat certain skin conditions, especially psoriasis. PUVA combines a psoralen drug and a controlled dose of longwavelength ultraviolet light.... puva

the most common form of *cutaneous T-cell lymphoma, with patches, plaques, and later nodules on the skin. It typically progresses very slowly and can be treated with topical corticosteroids, phototherapy, radiotherapy, or other agents.... mycosis fungoides

Yellowing of the skin and whites of the eyes in newborn babies, due to accumulation of bilirubin in the blood. It usually results from the liver being immature and unable to excrete bilirubin efficiently. This form of jaundice is usually harmless and disappears within a week. Rarely, severe or persistent neonatal jaundice is caused by haemolytic disease of the newborn, G6PD deficiency, hepatitis, hypothyroidism, biliary atresia, or infection.

Jaundiced babies usually require extra fluids and may be treated with phototherapy.

Exchange transfusion (see blood transfusion) may be needed in severe cases.

If severe neonatal jaundice is not treated promptly, kernicterus may occur.... jaundice, neonatal

Invisible light from the part of the electromagnetic spectrum immediately beyond the violet end of the visible light spectrum. Long wavelength ultraviolet light is termed , intermediate , and short.

Ultraviolet light occurs in sunlight, but much of it is absorbed by the ozone layer. The ultraviolet light (mainly ) that reaches the earth’s surface causes the tanning effects of sunlight and the production of vitamin D in the skin. It can have harmful effects, such as skin cancer (see sunlight, adverse effects of).

Ultraviolet light is sometimes used in phototherapy.

A mercury-vapour lamp (Wood’s light) can also produce ultraviolet light.

This is used to diagnose skin conditions such as tinea because it causes the infected area to fluoresce.... ultraviolet light

n. a common itchy skin disease characterized by reddening (*erythema) and vesicle formation, which may lead to weeping and crusting. It is endogenous, or constitutional, i.e. outside agents do not play a primary role (compare dermatitis), but in some contexts the terms ‘dermatitis’ and ‘eczema’ are used interchangeably. There are five main types: (1) atopic eczema, which affects up to 20% of the population and is associated with asthma and hay fever; (2) seborrhoeic eczema (or seborrhoeic dermatitis), which involves the scalp, eyelids, nose, and lips, is associated with the presence of Malassezia yeasts and may also be seen in HIV infection; (3) discoid (or nummular) eczema, which is characterized by coin-shaped lesions and occurs in adults, especially on the limbs; (4) *pompholyx, affecting the palms and soles; (5) gravitational (or stasis) eczema, associated with poor venous circulation and incorrectly known as varicose eczema.

Treatment of eczema is with regular emollients and topical corticosteroids. Other treatments include topical *calcineurin inhibitors, phototherapy, and systemic immunosuppressants. There is emerging evidence that effective treatment of eczema helps to reduce the risk of subsequently developing asthma and hay fever. —eczematous adj.... eczema

(PDT, photoradiation therapy, phototherapy, photochemotherapy) 1. a treatment for some types of superficial cancers. A light-sensitive agent (porfimer sodium [Photofrin] or temoporfin [Foscan]) is injected into the bloodstream and remains in cancer cells for a longer time than in normal cells. Exposure to laser radiation produces an active form of oxygen that destroys the treated cancer cells. The laser radiation can be directed through a fibreoptic bronchoscope into the airways, through a gastroscope into the oesophagus, or through a cystoscope into the bladder. PDT causes minimal damage to healthy tissue, but as it cannot pass through more than about 3 cm of tissue, it is restricted to treating tumours on or just under the skin or on the lining of internal organs. Photodynamic therapy makes the skin and eyes sensitive to light for six weeks or more after treatment. 2. a treatment for wet age-related *macular degeneration that involves the intravenous injection of a light-sensitive agent (verteporfin, Visudyne) which passes to the abnormal leaking blood vessels in the retina. The agent is activated when a cold laser light is directed at the macula, sealing the abnormal vessels and thus preventing further leakage and macular damage. The effect is to limit visual loss and stabilize vision.... photodynamic therapy