Are You Confident of the Diagnosis?
What you should be alert for in the history
In cases caused by filariasis, the history will include having lived in an area where the disease is endemic. There is usually a history of asymmetrical swelling, although both limbs can be affected. The legs are the most commonly affected area (see Figure 1), although the arms can be affected and, less commonly, the breasts or genitals. Genital symptoms can include scrotal elephantiasis or a hydrocele. Swelling is initially reversible but then can become permanent, with associated skin changes. A history will include inflammatory episodes and associated systemic symptoms.
Characteristic findings on physical examination
Characteristic findings on physical examination include lymphedema or swelling, which is normally asymmetrical. Skin changes include skin folds (shallow or deep). Mossy foot or papular lesions can be seen in advanced disease; intertrigo between toes is common.
Expected results of diagnostic studies
Blood film is normally negative for active infection, as lymphatic damage is a sequelae of infection.
Diagnosis is clinical; there are no confirmatory tests. Imaging can be used when another cause for edema is suspected. It is prudent to exclude pelvic pathology and other possible causes of lymphedema (i.e. malignancy or radiation).
Who is at Risk for Developing this Disease?
All patients living or having lived in endemic areas are at risk for elephantiasis. Those who sleep without mosquito nets are at increased risk.
There are individual variations in infection and development of elephantiasis, and there may be several reasons for this. The most common nematode is Wucheria bancrofti, which is responsible for 90% of lymphatic filariasis. Brugia malayi is an etiological agent present in areas of Asia.
What is the Cause of the Disease?
The etiology of elephantiasis is lymphatic damage secondary to the nematode infection lymphatic filariasis.
The pathophysiology is permanent lymphatic dilatation and dysfunction. This leads to swelling and secondary infections resulting in chronic skin changes and continued risk of infection.
Systemic Implications and Complications
Complications include recurrent acute attacks. These take the form of cellulitis, affecting the lymphedematous area, with associated systemic symptoms. The cellulitis is thought to be mediated primarily by bacteria causing infection through entry lesions, although epidermal damage alone can be a cause of inflammation. Lymphedema increases the risk of localized skin infections (both bacterial and fungal). These can cause entry lesions and increase the risk of acute attacks.
Conservative management is vital at all stages of disease and can prevent disease progression.
Skin should be cleaned by simply washing with soap and clean water. This can reduce acute attacks and therefore prevent the progression of disease.
Leg exercise and elevation are low-cost, easy-to-implement procedures, and are a very important adjunct to skin care. Compression can be helpful to reduce lympedema; however, in developing countries it can be difficult to to achieve good bandaging results due to the high humidity (bandaging in these conditions can actually encourage secondary infections).
Topical ointments, including antifungal and antibacterial medications, can be used to treat portal-of-entry lesions. It is especially important to concentrate on intertriginous areas. Suitable topical antifungal agents are miconazole or terbinafine. These can be applied to affected areas daily, after washing and drying. Potassium permanganate soaks can be used if there is oozing and odor, and to prevent bacterial infections. Any areas of dry skin should be treated with emollients. Locally available products (e.g. coconut oil) can be used.
Systemic treatments include prophylactic antibiotics (penicillin), which can be used to reduce the frequency of acute attacks of secondary cellulitis if topical treatments are not sufficient. The recommended dose is 500mg daily.
Occasionally, surgery can be helpful for mossy foot or knobs, or discrete areas of lymphedematous skin. However, healing is a major problem and this modality is only rarely appropriate.
Optimal Therapeutic Approach for this Disease
Skin hygiene, through regular washing and appropriate antiseptics and emollients, should be the main therapeutic approach for all patients. Potassium permanagante is a cheap and readily available antiseptic.
Exercise and elevation of the limb are essential therapeutic measures to reduce swelling and prevent disease progression.
It is also important to treat entry lesions. A particular focus on intertriginous areas between toes and skin folds is essential. These should be evaluated, if possible, by a swab for cultures to determine the cause of secondary infection, and any infection should be treated appropriately.
Penicillin V can be used prophylactically (as long as there are no contraindications) if recurrent episodes of secondary cellulitis are frequent.
Surgery can be considered in certain settings on rare occasions.
Antifilarial medication is important if there is any evidence of active filarial infection. Treatments are a single dose of albendazole 400mg, diethylcarbamazine 50mg, or ivermectin 0.2mg/kg.
There is some evidence that Wolbachia (a symbiotic bacteria with lymphatic filariasis) increase inflammation; treatment with doxycycline (200mg per day for 6 weeks) may be a useful adjunct to skin care.
Patients should be offered support and help with the long-term management of this chronic condition. This can be managed through patient support groups and nurse support. Support can encourage patient compliance with limb exercises and hygiene. Compression can offer additional reduction in certain situations, but in resource-poor settings can increase risk of secondary infections.
Unusual Clinical Scenarios to Consider in Patient Management
Any area of chronic lymphedema is an immune-privileged site, and for this reason there is a risk of local skin cancers (e.g. lymphagiosarcoma). Any nonhealing ulcer should raise suspicions and may require diagnostic biopsy, if facilities exist.
What is the Evidence?
Addiss, DG, Louis-Charles, J, Roberts, J, Leconte, F, Wendt, JM, Milord, MD. “Feasibility and effectiveness of basic lymphedema management in Leogane, Haiti, an area endemic for bancroftian filariasis”. PLoS Negl Trop Dis. vol. 4. 2010. pp. e668(Recent review providing evidence for effectiveness of basic management of lyphedema)
McPherson, T, Persaud, S, Singh, S, Fay, MP, Addiss, DG, Nutman, TB. “Interdigital lesions and frequency of acute dermatolymphangioadenitis in lymphœdema in a filariasis-endemic area”. Br J Dermatol. vol. 154. 2006. pp. 933-41. (Study showing importance of skin lesions and particularly toe-web lesions in etiology of acute episodes in lymphedema)
Taylor, MJ, Hoerauf, A, Bockarie, M. “Lymphatic filariasis and onchocerciasis”. Lancet. 2010. pp. 1175-85. (Recent review with latest evidence base and rationale for treatment)
McPherson, T. “Impact on the quality of life of lymphœdema patients following introduction of a hygiene and skin care regimen in a Guyanese community endemic for lymphatic filariasis: a preliminary clinical intervention study”. Filaria Journal. vol. 2. 2003. pp. 1(Study demonstrating limited resources needed to have impact on skin disease and quality of life in endemic community)
Debrah, AY, Mand, S, Marfo-Debrekyei, Y. “Reduction in levels of plasma vascular endothelial growth factor-A and improvement in hydrocele patients by targeting endosymbiotic Wolbachia sp. in Wuchereria bancrofti with doxycycline”. Am J Trop Med Hyg. vol. 80. 2009. pp. 956-63. (The Wolbachia “story”—an alternative approach to treatment)
Bockarie, MJ, Taylor, MJ, Gyapong, JO. “Current practices in the management of lymphatic filariasis”. Expert Rev Anti Infect Ther. vol. 7. 2009. pp. 595-605. (Good review of lymphedema treatment)
Witt, C, Ottesen, EA. “Lymphatic filariasis: an infection of childhood”. Trop Med Int Health. vol. 6. 2001. pp. 582-606. (Provides understanding that infection is transmitted in childhood and leads to subclinical lymphatic damage)
Dreyer, G, Medeiros, Z, Netto, MJ, Leal, NC, de Castro, LG, Piessens, WF. “Acute attacks in the extremities of persons living in an area endemic for bancroftian filariasis: differentiation of two syndromes”. Trans R Soc Trop Med Hyg. vol. 93. 1999. pp. 413-7. (The first study to clearly delineate acute episodes and provide understanding into the importance of acute episodes that were secondary to lymphedema)
Babu, S, Bhat, SQ, Pavan Kumar, N. “Filarial lymphedema is characterized by antigen-specific Th1 and Th17 proinflammatory responses and a lack of regulatory T cells”. PLoS Negl Trop Dis. vol. 3. 2009. pp. e420(Outline of immunology of lymphatic filariasis)
Copyright © 2017, 2013 Decision Support in Medicine, LLC. All rights reserved.
No sponsor or advertiser has participated in, approved or paid for the content provided by Decision Support in Medicine LLC. The Licensed Content is the property of and copyrighted by DSM.