Photo Quiz

Necrotic Wound on the Hand

Am Fam Physician. 2008 Nov 15;78(10):1209-1210.

A 51-year-old man presented with a lesion on his hand. The patient had recently returned from a trip to the midwestern United States and said that an insect may have bitten him. The rash began as a nonpainful, papular lesion measuring approximately 4 to 5 mm. Over one week, the lesion grew progressively in size, and multiple painful ulcerations developed (see accompanying figure). The patient had no previous rashes, and he denied having fever, chills, or recent illness. He had a history of significant hypertension, which was controlled with lisinopril (Zestril), 40 mg daily. He did not have a history of surgery, and his family and social histories were noncontributory.

Physical examination demonstrated normal vital signs, and the patient was afebrile. The examination of the hand revealed erythema and swelling over the dorsum of the affected hand with multiple ulcerations. There was no associated lymphadenopathy or other remarkable physical examination findings.

Question

Based on the patient's history and physical examination, which one of the following is the most likely diagnosis?

A. Brown recluse spider bite.

B. Herpes zoster.

C. Latent syphilis.

D. Melanoma.

E. Pyogenic granuloma.

Discussion

The answer is A: brown recluse spider bite. The brown recluse spider (Loxosceles reclusa) is found throughout the midwestern United States. The brown recluse spider bite is capable of causing necrotic wounds.1 In addition to the characteristic physical findings, the diagnosis is based primarily on a careful history.

Early diagnosis is key in avoiding many of the potential complications associated with brown recluse spider bites; necrotizing fasciitis is the most serious complication.2 Tissue damage in the area surrounding the bite causes a painful infarction of the skin that may heal slowly.3 If envenomation occurs, the lesion typically develops into a necrotic ulcer.4

Envenomation with the sphingomyelinase D2 enzyme is thought to be responsible for activating vascular endothelial cells, leading to tissue necrosis.2,4 In addition, sphingomyelinase D2 damages the myelin sheaths, thereby heightening the sensation of pain that is often associated with necrotizing fasciitis.

Treatment of most brown recluse spider bites requires only supportive care,5 such as RICE (rest, ice, compression, elevation) therapy. Nonsteroidal anti-inflammatory drugs, including aspirin, and antihistamines are also used initially to control the inflammatory response. Tetanus prophylaxis should be considered in patients with more progressed lesions because open lesions might increase the risk of tetanus. If there are signs of cellulitis, antibiotics (e.g., erythromycin, a cephalosporin) should be administered.

Treatment with topical dapsone or nitro-glycerin has also been suggested.5,6 Topical dapsone is thought to minimize tissue destruction by suppressing neutrophils, although this is controversial.6 Topical dapsone is effective only if administered within hours of envenomation. Its adverse effects, however, may be severe and include dose-related hemolysis, aplastic anemia, and agranulocytosis, but these effects usually occur with oral doses. In addition, patients with glucose-6-phosphate dehydrogenase deficiency should not receive dapsone.

Topical nitrates seem to enhance circulation and, therefore, assist in tissue repair. The effectiveness of nitrate treatment has not been proven.

Herpes zoster is characterized by a vesicular or bullous eruption limited to a dermatome innervation. Latent syphilis is the stage of the infection in which there are no clinical signs or symptoms. Melanoma usually presents as a pigmented lesion. Pyogenic granuloma presents as a rapidly developing papule with capillary proliferation that bleeds easily.

Summary Table

Condition Characteristics

Brown recluse spider bite

Rapidly transforming lesions that may ulcerate and necrotize the dermal layers

Herpes zoster

Vesicular or bullous eruption limited to a dermatome innervation

Latent syphilis

Usually, no signs of infection are apparent at this stage

Melanoma

Pigmented lesion that develops much slower than a spider bite

Pyogenic granuloma

A rapidly developing papule with capillary proliferation that bleeds easily

Summary Table

View Table

Summary Table

Condition Characteristics

Brown recluse spider bite

Rapidly transforming lesions that may ulcerate and necrotize the dermal layers

Herpes zoster

Vesicular or bullous eruption limited to a dermatome innervation

Latent syphilis

Usually, no signs of infection are apparent at this stage

Melanoma

Pigmented lesion that develops much slower than a spider bite

Pyogenic granuloma

A rapidly developing papule with capillary proliferation that bleeds easily

Address correspondence to Steven N. Glavas, DO, MPH, at snglavasdo@pol.net. Reprints are not available from the author.

Author disclosure: Nothing to disclose.

REFERENCES

1. Wong RC, Hughes SE, Voorhees JJ. Spider bites. Arch Dermatol. 1987;123(1):98–104.

2. Majeski J. Necrotizing fasciitis developing from a brown recluse spider bite. Am Surg. 2001;67(2):188–190.

3. Anderson PC. Spider bites in the United States. Dermatol Clin. 1997;15(2):307–311.

4. Williams ST, Khare VK, Johnston GA, Blackall DP. Severe intravascular hemolysis associated with brown recluse spider envenomation. A report of two cases and review of the literature. Am J Clin Pathol. 1995;104(4):463–467.

5. Wright SW, Wrenn KD, Murray L, Seger D. Clinical presentation and outcome of brown recluse spider bite. Ann Emerg Med. 1997;30(1):28–32.

6. Wendell RP. Brown recluse spiders: a review to help guide physicians in nonendemic areas. South Med J. 2003;96(5):486–490.

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