Dermatology 35

Pruritus: causes and management

Pruritus, or the desire to scratch, is a common that increases in incidence with age. It may be the result of a primary cutaneous disorder or may be a symptom of an underlying systemic disease. In this article, Drs Nevianna Tomson and Nigel Burrows outline some of the conditions that can cause pruritus in the elderly and discuss the various ways it can be managed.

ruritus is defi ned as the unpleasant sensation Itching as a result of xerosis is common in the that elicits a desire to scratch. It can be elderly. Pruritus is usually intense and often Pclassifi ed into pruritoceptive (cutaneous in involves the anterolateral aspect of the lower legs, origin; eg, scabies), neuropathic (due to lesions of back and waist, but may be generalised. Winter is a afferent pathways of the nervous system; eg, brain peak time for presenting with xerosis due to the tumours), neurogenic (due to centrally acting low humidity in ambient air and use of heating mediators; eg, opioid peptides of cholestasis) and systems that force hot, dry air into the psychogenic. The two major peripheral mediators environment. in an are histamine and the neuropeptide substance P. Although often perceived as trivial, Dry skin may present with redness, scaling or pruritus can be very distressing and socially cracks. The cracks resemble those seen in fi ne disabling – resulting in serious impairment of an antique porcelain (eczema craquelé) and are a individual’s quality of life. Persistent pruritus result of the loss of hydration in the epidermis. As occurs in up to 30 per cent of elderly people1. It they extend and deepen, they form fi ssures that may be a result of a number of primary skin eventually reach the depth of dermal capillaries diseases, systemic diseases, medications or, when causing bleeding. Emollients close these cracks and no abnormality can be found, as a consequence of fi ssures by fi lling spaces around desquamating the ageing process of the skin. (peeling) – but attached – skin fl akes sealing moisture into the skin through the production of an is a Specialist Registrar and occlusive barrier and thereby softening the skin3, 5. is a Consultant Dermatologist at the Xerosis Many elderly people suffer from dry skin (xerosis). Ingredients in emollients include mineral oils This may be as much as 75 per cent of those aged (eg, liquid paraffi n, petrolatum), waxes (eg, lanolin, 64 years and older2. A reduction in the activity of beeswax, carnauba), long-chain esters, fatty acids, sebaceous and sweat glands, and a decrease in and mono-, di- and triglycerides6. Most sterol esters and triglycerides with advancing age, preparations for dry skin use a combination of may be responsible3, 4. Water loss from skin is the these. Emollients are the only effective treatment

NIGEL BURROWS same as in younger individuals, but the water for xerosis-related pruritus. Systemic content of the epidermis is slightly reduced in antihistamines and topical or systemic steroids are DR NEVIANNA TOMSON DR Dermatology Department, Addenbrookes Hospital, Cambridge ageing skin which may also contribute. ineffective and should not be prescribed7.

july 2006 / midlife and beyond / geriatric medicine 36 Dermatology

role in relieving itch, which indicates that histamine Primary skin diseases is not the sole pruritogen. The main benefi cial The fi rst presentation of primary skin disease effects of antihistamines are thought to be from may occur in old age and cause pruritus. The their sedative effects. For this reason sedating following skin conditions in the elderly therefore antihistamines are preferred, although they should need to be considered. be used with caution since the elderly often have co-morbidity. Emollients and topical steroids are helpful, and occasionally systemic agents are Scabies needed to control symptoms. Institutionalised care, such as nursing and residential homes, predispose the elderly patient to contagious aetiologies of pruritus. With scabies, Allergic contact pruritus usually occurs four to six weeks following This is a delayed type IV hypersensitivity response infestation with the Sarcoptes scabiei mite. It is to a substance on contact with the skin. It presents usually generalised, affecting all areas except the with an acute or subacute eczema, with intense face, but is worse over the hands, forearms, thighs irritation, pruritus, blistering and weeping of the and genitals. Often other family or care home skin following exposure to an allergen the patient members have similar symptoms or have already has become sensitised to in the past. The original been diagnosed with scabies. site of the eruption often gives a clue to the likely causative allergen. Common allergens in the The diagnosis is confi rmed by identifying elderly include topical medicaments such as serpentiginous linear tracks (burrows) usually antihistamines, anaesthetics aminoglycosides, located along the sides of the fi ngers, palms or lanolin and parabens. Other sensitisers include wrists. Affected individuals also typically have an rubber in gloves and shoes, plastics in hearing aids erythematous papular eruption on the trunk and and spectacle frames, and plants and chemicals in limbs as a result of an allergic reaction to the mite. hair dyes. Diagnosis is made from the history and Occasionally extensive infestations occur with the distribution of the rash, and can be confi rmed by mite resulting in a myriad of burrows and crusting patch testing. and scaling of the skin, which may include the face. This is termed Norwegian (crusted) scabies and is more commonly found in institutions such as Urticaria nursing homes. Urticaria (hives) is a common reaction pattern in which pink, itchy swellings (wheals) occur The most commonly used preparations to treat anywhere on the body as a result of mast cell scabies are Malathion 0.5 per cent lotion and degranulation. Individual wheals last less than Permethrin fi ve per cent cream, but numerous 24 hours, but new lesions may continue to appear other preparations are available. Ivermectin at a for days or months. Urticaria is idiopathic in most single dose of 150-200mg/kg body weight is usually patients. However, a drug history should be reserved for Norwegian scabies. Although obtained from all patients – especially in the treatment eradicates the mite, the itch – which is elderly (who often have polypharmacy), as a drug mainly due to an allergic reaction to the mite – may occasionally be responsible. Because often persists for up to a month. Topical steroids, histamine plays a primary role in the pruritus of crotamiton (Eurax) cream and emollients may be urticaria, H1-receptor antagonists (antihistamines) needed for symptomatic relief. improve or relieve itch in almost every patient. The dose should be carefully titrated up in the elderly.

Atopic dermatitis Late onset is uncommon. It Bullous pemphigoid presents with an erythematous ill-defi ned rash with Bullous pemphigoid is a chronic immunobullous fi ne scaling; in the acute state, it presents with disease of the elderly presenting with tense pruritic oedema, vesiculation, serous exudates and crusting. blisters on normal or erythematous skin. However, It is usually symmetrical and may affect any part of occasionally patients may present with generalised the body. The mediators of pruritus in atopic pruritus without blisters or with a prodromal dermatitis have not been clearly identifi ed despite pruritic, urticarial or eczematous eruption. In extensive research. Antihistamines have a limited limited disease, very potent topical corticosteroids

geriatric medicine / midlife and beyond / july 2006 38 Dermatology

may be suffi cient in controlling it. However, most patients also require oral prednisolone at relatively Pruritus without primary skin high doses and are thus at risk of the complications disease of systemic steroids. Steroid sparing agents such as The term ‘generalised pruritus’ is usually used to azathioprine or tetracyclines may be required. describe itching in the absence of dermatological disease or skin rash. Examination of the skin reveals either no abnormality or excoriations Dermatitis herpetiformis resulting from scratching. In these patients Dermatitis herpetiformis (DH) presents as a examination and investigation for an underlying chronic pruritic papulovesicular eruption typically cause is vital as the presence of systemic disease involving the elbows, knees, buttocks and scalp. has been reported as high as 10–50 per cent8. In the Although the most common onset age is 30–40 absence of primary skin disease, polypharmacy as years, it can present in the elderly. Dapsone is the well as systemic disease, needs to be considered. drug of choice in the management of DH, starting with a dose of 25mg per day and titrating up if necessary. Symptomatic improvement may be Senile pruritus noticeable in as little as 24 –48 hours, but treatment When no underlying cause for generalised pruritus may be required for months or even years. can be found, the term ‘senile pruritus’ is often used. It has been suggested that this pruritus is a The signifi cant risk of haemolysis may, result of arteriosclerosis of the blood vessels that however, preclude its use in patients with severe supply the nervous tissue in the skin. However in ischaemic heart disease. A gluten-free diet may one study, 142 out of 162 elderly patients had an also help the symptoms and allow a reduction in identifi able cause for their itching (including the dose of dapsone. xerosis) and only 20 had true senile pruritus9. Thus, senile pruritus is a diagnosis made only by exclusion of other pathologies. Management is Psoriasis diffi cult and emollients and antihistamines alone Although not considered to be a pruritic disorder, rarely alleviate the problem. Anecdotal reports psoriasis is associated with variable degrees of suggest that gabapentin, serotonin antagonists and pruritus in up to 84 per cent of patients7. The UVB may attenuate itch in some of these patients. treatment of psoriasis in the elderly is the same as in younger patients, although systemic medication is used with more caution due to the increased risk Drugs of adverse effects. Opiates, aspirin, vitamin B complex and systemic retinoids are recognised to cause pruritus.

Prurigo nodularis This condition results from chronic and severe scratching and presents with small fi rm Cholestasis may be a result of liver disease (eg, erythematous nodules, usually over extensor primary biliary cirrhosis or drugs such as surfaces of the limbs or buttocks. Longstanding erythromycin). It may be localised to the hands and lesions may become verrucous, lichenifi ed or feet or be a generalised itch. Cholestatic pruritus is fi ssured, and resolve to leave signifi cant post- associated with high plasma levels of bile salts, infl ammatory hyperpigmentation. An underlying although there is no direct correlation between cause for pruritus is not always found. concentration of bile salts and itch. Medication such as cholestyramine, which lowers bile salts, Antihistamines, wearing gloves at night and may improve this type of pruritus. Hepatitis C may trimming fi ngernails may also be helpful. Topical cause intense pruritus and should be considered, or intralesional corticosteroids (if lesions are few in although it is less common in the elderly. number) may be helpful. Occlusion with bandaging is often used in the management of nodular . If lesions are numerous, psoralen and Renal pruritus ultraviolet An irradiation (PUVA) or ultraviolet B Uraemia is a common cause of pruritus in chronic (UVB) phototherapy can help. In very severe cases renal failure. Approximately 80 per cent of oral thalidomide may be considered. patients on maintenance dialysis complain of

geriatric medicine / midlife and beyond / july 2006 Dematology 39

itch10,11. The mechanism is unknown. Renal transplantation is the only reliably effective References treatment of renal pruritus. Topical steroids and 1. Beauregard S, Gilchrest BA. A Mosby, 2002 survey of skin problems and 9. Young AW. The diagnosis of antihistamines are usually of limited benefi t but skin care regimens in the pruritus in the elderly. J Am elderly. Arch Dermatol 11987;987; Geriatr Soc 1967; 15: 750-8 phototherapy with narrowband UVB may be 123: 1638-43 10. Gilchrest Ba, Stern RS, helpful. Emollients may provide relief in those with 2. Heymann WR, Gans EH, Steinman TI, et al. Clinical Manders SM, et al. Xerosis in features of pruritus among dry skin. For localised pruritus, capsaicin 0.025 per hypothyroidism: a potential patients undergoing role for the use of topical maintenance haemodialysis. cent cream can be tried. Parathyroidectomy in thyroid hormone in euthyroid Arch Dermatol 11982;982; 118: patients. Med Hypotheses 154-60 patients with secondary hyperparathyroidism may 2001; 57: 736-739 11. Szepietowski JC, Schwarz RA. be effective in relieving pruritus. 3. Norman RA. Xerosis and Uraemic pruritus. Int J pruritus in the elderly: Dermatol 11998;998; 37: 247-53 recognition and management. 12. Archer CB, Camp RDR, Dermatol Ther 2003; 16: 254- Greaves MW. Polycythaemia 259 vera can present with 4. Ademola J, Frazier C, Kim SJ, [letter]. The Thyroid disease et al. Clinical evaluation of Lancet 11988;988; ii:: 11451451 Both hypothyroidism and hyperthyroidism may 40% urea and 12% ammonium 13. Feiner AS, Mahmood T, lactate in the treatment of Wallner SF. Prognostic cause pruritus. The mechanisms postulated are dry xerosis. Am J Clin Dermatol importance of pruritus in 2002; 3: 217-222 Hodgkin’s disease. JAMA skin in the former and increased skin temperature 5. Jennings MB, Alfi eri DM, 1978; 240: 2738-40 due to increased cutaneous blood fl ow in the latter. Parker ER, et al. A double-blind 14. Paul R, Paul R, Jansen CT. clinical trial comparing the Itch and malignancy prognosis Correcting the underlying cause is necessary, but effi cacy and safety of pure in generalised pruritus: a 6- lanolin versus ammonium year follow-up of 125 patients. emollients may also be helpful – especially if dry lactate 12% cream for the J Am Acad Dermatol 11987;987; 16: skin is present in the hypothyroid patient. treatment of moderate to severe 1179-82 foot xerosis. Cutis 2003; 71: 15. Newbold PCH. 78-82 Antidepressants and skin 6. Lodén M. Role of topical disease. BMJ 1988; 298: 379 emollients and moisturizers in 16. Taddese A, Nah SY, the treatment of dry skin barrier McCleskey EW. Selective Diabetes mellitus disorders. Am J Clin Dermatol opioid inhibition of small Type 2 diabetes mellitus is common in the elderly 2003; 4: 771-788 nociceptive neurones. Science 7. Bolognia JL, Jorizzo JL, Rapini 1995; 270: 1366-9 but it is not a cause of pruritus. Patients are more RP. Dermatology, 1st edn. 17. Zylicz Z, Smits C, Krajnic M et Mosby, 2003 al. Paroxetine for pruritus in susceptible to cutaneous infections, such as 8. Lebwohl MG, Heymann WR, advanced cancer. J Pain candidiasis, which may present with pruritus. Berth-Jones J. et al. Treatment Symptom Manage 1998; 16: of skin disease, 1st edn. 121-4

may be a feature in any visceral or haematological Iron defi ciency malignancy. Unfortunately, senile pruritus and Iron defi ciency is a common fi nding in the elderly, xerosis are common in the elderly who as a group which may occur with or without anaemia and be are also more at risk of malignancy. It is therefore the cause of generalised pruritus. It is often the only after considerable consideration of other result of a poor diet, but an underlying malignancy causes that a patient should be screened for an must be excluded if it presents with anaemia. underlying malignancy. In a six-year follow-up study of 125 patients with generalised pruritus, no signifi cant overall increase in malignant neoplasms Polycythaemia rubra vera was found (the mean age of patients in this study Polycythaemia rubra vera presents with itching was 46 for women and 63 for men14). after a warm bath or shower (aquagenic pruritus), and this symptom may precede the diagnosis by several years12. Bathing by regional sponging may help although antihistamines have a limited role. Brachioradial pruritus (BRP) presents as a Successful treatment of the polycythaemia may not localised itch over the lateral aspect of one or both relieve the itch. Correction of venesection-induced arms, and less commonly on the shoulders and iron defi ciency may be helpful, but there is a risk it upper trunk. Symptoms show strong seasonal may worsen the underlying polycythaemia. PUVA variation with itch exacerbated by exposure to is sometimes successful. strong sunlight in the summer. It has been suggested BRP results from sunlight-induced damage to cutaneous nerve endings or rarely by Malignancy cervical root damage due to degenerative Intense prolonged generalised pruritus may arthropathy, cervical rib or spinal tumours. BRP is precede the diagnosis in Hodgkin’s lymphoma and often refractory to topical or oral corticosteroids indicate a poorer prognosis13. Other malignancies and antihistamines, but topical capsaicin cream or do not usually present with pruritus, but itching gabapentin may be helpful.

july 2006 / midlife and beyond / geriatric medicine 40 Dermatology

cause. A pruritus screen (Table 1) may be helpful in Psychological this. Symptomatic relief is the next step, and even A variety of psychological disorders may present more vital if a cause for the itch cannot be identifi ed. with itching. These include depression, General measures such as keeping the environment anxiety disorders, obsessive-compulsive cool, wearing cotton light clothing and bedclothes, disorder, personality disorder, psychosis and and using cooler water when bathing may be helpful. eating disorders. Parasitophobia is a delusion of Emollients, one to two per cent menthol in aqueous parasitic infestation of the skin and usually cream, topical corticosteroids and oral low-sedating presents with pruritus alone. Patients may bring in antihistamines can also provide symptomatic relief – particulate material they believe represents the although the latter must be used with caution in the parasites or insects causing the itch. Treatment is elderly. Ultraviolet light (PUVA or UVB) treatment rarely successful and usually involves is most effective in pruritus secondary to antidepressant and anxiolytic drugs along with a infl ammatory dermatoses, chronic renal failure, psychiatric referral. Pimozide is a phenothiazine primary biliary cirrhosis, polycythaemia rubra vera that has been specifi cally advocated for the and . Systemic tricyclic treatment of delusions of parasitosis15. antidepressants have been shown to be helpful in some patients with intractable itching. More recently, the use of opioid-receptor antagoinists (eg, Treatment naloxone)16 and selective serotonin reuptake The most important step in the management of inhibitors (eg, paroxetine)17 in intractable pruritus pruritus is to identify and treat any underlying have shown promising results. Further research into Dermatology 41

Key points Table 1. Screening for treatment

Investigation Condition causing > Pruritus is common in the elderly and may be pruritus the result of skin disease, a systemic cause, Full blood count Microcytic hypochromic medication or due to xerosis in ageing skin. anaemia in iron defi ciency NormochromicNormochromic nnormocyticormocytic > In the absence primary skin disease, a pruritus anaemiaanaemia iinn cchronichronic ddiseaseisease aandnd Hodgkin’s lymphoma blood screen is useful. Polycythaemia in PRV > Symptomatic relief with emollinets, topical Serum iron and ferritin Iron defi ciency steroids and antihistamines can be helpful. Urea and creatinine Renal impairment Glucose Diabetes mellitus Liver function test Increased bilirubin and the neurophysiological pathways for itch should lead alkaline phosphatase in to better management of pruritis. obstructive jaundice Thyroid function tests Hypo- or hyperthyroidism Chest radiograph Bronchial malignancy Pruritus increases in incidence with age and Hilar lymphadenopathy may be due to a primary cutaneous disorder or be a in Hodgkin’s disease symptom of an underlying systemic disease. In the Immunoglobulins and serum Myeloma protein electrophoresis absence of primary skin disease, polypharmacy as Urine dipstick For glucose in diabetes well as systemic disease need to be considered. mellitus Blood and protein in renal disease. Declared confl ict of interest: none declared.