New-Onset Purpura in a Patient with Recently Diagnosed Temporal Arteritis

Diagnosis: Disseminated strongyloidiasis.

Our patient received treatment with thiabendazole and ivermectin via nasogastric tube. Despite the appropriate antimicrobial and aggressive supportive treatment, she died on day 23 of hospitalization, ∼2 months after commencing prednisone treatment for biopsy-proven temporal arteritis.

Strongyloidiasis is an intestinal infection caused by the parasitic nematode Strongyloides stercoralis. Distinctive characteristics of this parasite include its ability to persist and replicate within the host for decades, producing minimal or no symptoms, and its potential to cause life-threatening infection in a host with a compromised immune system [1–3].

Strongyloidiasis affects 30–100 million people worldwide, and it is endemic in Southeast Asia, Latin America, sub-Saharan Africa, and parts of the southeastern United States [2]. In the United States, the highest prevalence rates (4%) are found in eastern Kentucky and rural Tennessee [3]. Our patient was born and raised in Kentucky and had lived in Dayton, Ohio, for 60 years. We speculate that she acquired the infection in early childhood while walking barefoot in soil contaminated with S. stercoralis larvae.

Chronic infection with S. stercoralis is often asymptomatic or may cause nonspecific gastrointestinal, pulmonary, or cutaneous symptoms [1–6]. Our patient had a long history of “stomach ulcers” but no other obvious manifestation of strongyloidiasis until she commenced steroid treatment. Steroid therapy is the most important factor for conversion of uncomplicated into complicated strongyloidiasis [1–6]. Two forms of complicated strongyloidiasis have been reported: hyperinfection syndrome and disseminated strongyloidiasis [1]. The former is an acceleration of the normal life cycle of S. stercoralis, leading to excessive worm burden without spread of the larvae outside the usual migration pattern (e.g., gastrointestinal tract and lungs). Disseminated strongyloidiasis involves widespread dissemination of larvae to other organs (e.g., skin, CNS, and heart) not ordinarily part of the parasitic life cycle. It is characterized by diverse pulmonary and gastrointestinal manifestations, development of sepsis caused by enteric microorganism(s), and multiorgan failure. The mortality rate can be as high as 89% [1–6].

The pathognomonic skin lesion of chronic strongyloidiasis is a distinctive form of cutaneous larva migrans named “larva currens” (“racing larva”). The lesion is thought to be caused by the rapid rate of intradermal migration of the larvae. It is a pruritic, linear to serpiginous, erythematous urticarial lesion that moves at a rate of 5–15 cm/h [1, 4–6]. The most common sites of involvement are the buttocks, thighs, groin, and trunk [6].

Skin involvement in disseminated strongyloidiasis is uncommon, but, when present, it manifests as petechial and purpuric rash, most commonly involving the trunk and proximal portion of the extremities, as exemplified by our patient (figures 1 and 2) [4–6]. The rash is caused by destruction of the small dermal vessels during massive dissemination of filariform larvae into the skin [4–6]. Skin biopsy frequently demonstrates fragments of filariform S. stercoralis in the dermis.

Figure 1

Extensive petechial and purpuric rash involving the trunk and thighs

Figure 2

Close-up of petechial and purpuric rash

Definitive diagnosis of strongyloidiasis is made by recovering larvae from a stool sample or other specimen [1–3]. Repeated stool examinations or use of special methods (e.g., agar plate) are often necessary because of the small and intermittent larval excretion [1–3]. The diagnosis of strongyloidiasis in our patient was made when larvae were noted in the skin biopsy (figure 3) and colon specimens (figure 4). However, the diagnosis was delayed, and she died as a result of heavy parasitic burden, despite having received appropriate treatment.

Figure 3

Histopathologic examination of the skin showing Strongyloides stercoralis filariform larva in the dermis (hematoxylin and eosin stain; original magnification, ×400).

Figure 4

Histopathologic examination of the resected colon and terminal ileum showing ulceration, acute inflammatory infiltrate, and involvement of the mucosa and submucosa by Strongyloides stercoralis larvae (hematoxylin and eosin stain; original magnification, ×400).

The goal of treatment for strongyloidiasis is the complete eradication of S. stercoralis larvae. All infected patients should be treated to prevent the development of complicated strongyloidiasis. Ivermectin, at a dosage of 200 μg/kg daily for 1–2 days, is more effective and better tolerated then thiabendazole (25 mg/kg twice daily for 2 days) or albendazole (400 mg twice daily for 3 days) [1–3]. For disseminated strongyloidiasis, prolonged treatment (7–14 days) and repeated courses are necessary for eradication of S. stercoralis.