Nodular Prurigo: an Overview of Diagnosis and Management
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CLINICAL REVIEW Nodular prurigo: An overview of diagnosis and management Sheila Ryan ABSTRACT Nodular prurigo is a chronic inflammatory skin disease characterised by severe pruritus, nodules, papules, excoriations and ulceration. It is a can be a very distressing disorder for the sufferer. The condition is linked with a variety of disorders including atopic eczema, chronic renal failure, hyperthyroidism, iron deficiency anaemia, obstructive biliary disease, gastric malignancy, lymphoma, leukaemia, hepatitis B and C, HIV and depression. Nodular prurigo affects all ages and commonly occurs between the ages of 20 to 60 years. There are a range of treatments available for nodular prurigo, but their use is based on anecdotal rather than empirical evidence. The range of treatments will be discussed here. The nurse has an important role in guiding and supporting patients with this difficult, often frustrating condition. Citation: Ryan S. Nodular prurigo: An overview of diagnosis and management. Dermatological Nursing 2017. 16(4): 18-21 Introduction of disorders including atopic eczema, Nodular prurigo is a chronic chronic renal failure, hyperthyroidism, iron infl ammatory skin disease characterised defi ciency anaemia, obstructive biliary by severe pruritus, nodules, papules, disease, gastric malignancy, lymphoma, excoriations and ulceration.1 Dr James leukaemia, hepatitis B and C and HIV.1,4 Hyde fi rst described the condition in If nodular prurigo is solely as a result of 1909, which reported pruritic nodules scratching it is remarkable that it does on the lower extremities in middle-aged not evolve in more patients with chronic women.2 The condition is also known pruritic conditions.3 as prurigo nodularis, Hyde’s disease, prurigo simplex chronicus, lichen obtusus Nodular prurigo is also linked corneus and nodular neurodermatitis with psychiatric disorders including circumscripta.1 depression and anxiety.3 The relationship here is also unclear. Aetiology There is debate within the literature The cause of nodular prurigo is poorly whether there is an increased risk understood. It is not clear whether the of developing nodular prurigo in condition is solely the result of chronic psychiatric conditions. scratching or a disease in itself.3,4 Nodular Notwithstanding, there is also prurigo is associated with a variety evidence that while there is a higher Table 1. Associated Disorders Classifi cation Associated diseases Dermatological Atopic eczema, psoriasis, bullous pemphigoid, linear IgA, scabies, T-cell lymphoma Internal disorders Anaemia, kidney disease, cholestatic disorders, diabetes, polycythaemia vera, HIV, hepatitis B and C, lymphoma and malignancies Sheila Ryan is a Registered Advanced Nurse Practitioner at the Department Neurological Notalagic paraesthecia, multiple sclerosis, brachioradial pruritus of Dermatology, University of Limerick Psychosomatic/psychiatric Parasitosis, depression, schizophrenia Hospital Group, Limerick, Ireland. 18 Dermatological Nursing, 2017, Vol 16, No 4 www.bdng.org.uk Journal 17 16-4 C product.indd 18 12/7/17 2:20 PM CLINICAL REVIEW incidence of psychiatric co-morbidities Nodular prurigo will rarely resolve are usually suffi cient for diagnosing the in individuals with nodular prurigo spontaneously.8 condition.10 The fi rst step is to exclude than healthy controls, the same any underlying disease and then to incidence is seen when compared Diagnosis and differential diagnosis address cause of general pruritus.10 with patients with other pruritic The clinical features of nodular prurigo Potential investigations include: dermatoses.5 It is thought that there is a cascade of events in developing nodular prurigo.1 The condition starts with chronic and severe pruritus. This in turn induces mechanical trauma through scratching. This subsequently leads to the recruitment of a lymphocyte rich infl ammatory infi ltrate, tissue modelling and the activation as well as proliferation of peripheral nerves.1 Epidemiology Nodular prurigo affects both sexes equally. The commonest age is 20 to 60 years. However the condition does affect children.6 Nodular prurigo at a younger age is more commonly Figure 1 associated with atopic eczema.4 Localised nodular prurigo Clinical Presentation The patient will have a longstanding chronic pruritus.7 The patient will complain of an intense severe itch in the area affected by nodular prurigo. Nodular prurigo lesions are fi rm papules/nodules that are ≤2cm in diameter (Figure 1). The lesions may be warty, scally, excoriated, or crusted, and may number from a few to hundreds (Figure 2). Nodules often start as a red, itchy lump.8 Older lesions can be grey/ purple in colour and are sometimes hyperkeratotic, or ulcerated (Figure 3).1 The skin between lesions is usually normal, but can be dry or lichenifi ed.8 The lesions tend to be distributed symmetrically and affect the extensor surfaces of arms, legs.8 The back, abdomen, buttocks and posterior neck are also frequently affected.4 However the face, palms and fl exural areas are rarely affected.4 Typically, the middle back is spared as the patient often cannot reach this site.1 This is sometimes referred to as the butterfl y sign and is a classic Figure 2 feature of nodular prurigo.1 Generalised nodular prurigo www.bdng.org.uk Dermatological Nursing, 2017, Vol 16, No 4 19 Journal 17 16-4 C product.indd 19 12/7/17 2:21 PM CLINICAL REVIEW where there is underlying xerosis.9 Dry skin is a well-known cause of pruritus. Therefore, patient education on soap avoidance and an effective emollient regime is important to reduce symptoms 8 Menthol based creams or ointments. These can be helpful in some cases. These creams and ointments can cool the skin, but the effects are temporary. It is often best used in limited disease 8 Capsaicin cream. This may also be effective, but it needs to be applied 4-6 times daily for at least 2 weeks and for up to 10 months.11 Figure 3 Capsaicin is made from chilli Eroded nodular prurigo pepper and it induces a burning sensation initially before it helps 8 Pruritus screen – full blood management is often the best method with itch.4 Due to the frequency of count, CRP, iron studies, urea and of treating the nodular prurigo application and the initial burning electrolytes, liver function tests, symptoms.4 Where this is not possible, sensation it is most effective in thyroid function tests, calcium and treatments that alleviate pruritus or limited disease glucose.7 These investigations will reduce scratching behaviour can be 8 N-acetylcysteine. This has help identify any underlying renal, used to treat the nodular prurigo recently shown to be effective liver, metabolic or infective cause.7 symptoms. in atopic eczema and other 8 HIV, hepatitis B and C screen.4 pruritic conditions such as nodular 8 Patch testing to identify contact Simple measures such as advising prurigo.12 It is available as an oral dermatitis.7 the patient on keeping nails short, and topical medicine. Topically it is 8 Skin biopsy of lesions in atypical wearing cotton gloves and keeping a N-acetylcysteine 10% in 5% urea. presentation.7 bathing water temperature lukewarm This formulation is malodorous are useful fi rst steps. Advising the with a sulphur smell. This odour In patients with severe disease, patient to limit exposure of pruritic can be improved with the addition where a cause cannot be determined skin to the air is also a useful tip. of 1.5% lavender, orange or potential malignancy should be out Nodular prurigo lesions are often rosemary oil ruled.4 more itchy when the skin is exposed. 8 Topical steroids. These are useful Also, when the skin is exposed, the in treating both localised and The differential diagnosis for pruritic areas are more accessible extensive nodular prurigo lesions. nodular prurigo includes dermatitis for scratching. Educating the patient They generally need to potent herpetiformis, scabies, lichen simplex on the role of scratching and the (e.g. betamethasone valerate 0.1%) chronicus, atopic eczema, allergic production of nodular prurigo or very potent (e.g. clobetasol contact dermatitis, hypertrophic lesions is of paramount importance. propionate) to be effective. lichen planus, perforating disorders, The nurse, as a skilled educator, has However, their long-term use is neurotic excoriations and multiple an important role in guiding and limited due to the potential for keratoacanthomas, dermatofi broma.4 encouraging patients undergoing skin atrophy.4 Steroid impregnated treatment. dressings (e.g. fl udroxycortide Management impregnated tape) can be used as Nodular Prurigo is a diffi cult condition Local treatments it is both anti-infl ammatory and to treat. The evidence for the majority There are a variety of local protective. Its use is restricted to of treatments is based on anecdotal treatments. The advantage of a local localised disease evidence rather than empirical studies. treatment is the relative low toxicity. 8 Intralesional steroid injections In the main treatments are aimed at The disadvantage is they are often (triamcinolone acetonide). These reducing or stopping the itch scratch restricted to local disease and the time are useful in treating resistant cycle. consuming nature of these treatments. localised lesions. They are anti- These treatments include: infl ammatory and the lesion will General measures 8 Emollients. These should be used usually fl atten within weeks of Where there is an identifi ed regularly to cool and moisturise treatment. If effective, treatment underlying associated cause, its the skin. This is especially important can be repeated at 4 weekly 20 Dermatological Nursing, 2017, Vol 16, No 4 www.bdng.org.uk Journal 17 16-4 C product.indd 20 12/7/17 2:21 PM CLINICAL REVIEW intervals. However, the treatment is effective than non-sedating in 2. Hyde JN. Prurigo Nodularis. In Hyde painful and is further limited by the the management of nodular JN, Montgomery FH, A practical treatise potential for skin atrophy prurigo. The benefi t of sedating on disease of the skin, for the use of students and practitioners 3rd ed.