RSS Feeds
-
Spider Bites (Mis)Masquerading as Infectious Cellulitis
Submit responseTo the Editor:
Falagas and Vergidis' et al useful review (1) omits a (too-)commonly encountered diagnostic consideration, i.e., whether cellulitis could be due to a spider bite. Clinicians often misdiagnose lesions as spider bites because spiders are so commonly found in the patient's vicinity but this is insufficient causative evidence as spiders are ubiquitous. In the United States, spider bites typically cause mild local, circumscribed erythema but rarely if ever result in dermonecrosis or ulcers (2); confusion with diseases characterized as ulcers such as anthrax, as occurred during the Postal Service incident, should not occur. They are also unlikely to lead to diagnostic confusion with cellulitis by a clinician who carefully considers the epidemiology and clinical presentation of a lesion.
Importantly, however, brown recluse spider bites may appear like cellulitis, with spreading erythematous margins and, in severe cases, central dermonecrosis (3). Physicians must know when to suspect brown recluse spider bites which, as with bites by other spiders, are commonly overdiagnosed (4). The range of the brown recluse spider is restricted to the south and central midwestern United States (http://spiders.ucr.edu/images/colorloxmap.gif ), and physicians outside of this area need not consider brown recluse spider bites as a possible cause of cellulitis (4). Bites by brown recluse spiders are infrequent, even in homes where the spider is common and, when they occur, usually do not cause more than local, self-limited erythema. Nevertheless, severe cases occur and distinguishing brown recluse spider bites from cellulitis is important because the therapeutic approach is different.
In the Pacific northwest, the bite of a hobo spider is commonly thought to cause cellulitis with dermonecrosis but the association of this spider with proven necrosis still needs verification (5).
George Schmid, M.D., M.Sc. World Health Organization Geneva, Swtizerland
Rick Vetter, M.S. University of California, Riverside Riverside, CA
1. Falagas ME, Vergidis PI. Narrative review: Diseases that masquerade as infectious cellulitis. Ann Intern Med 2005;142:47-55.
2. Isbister GK, Gray MR. A prospective study of 750 definite spider bites, with expert spider identification. QJM 2002;95:723-31.
3. Sams HH, Hearth SB, Long LL, Wilson DC, Sanders DH, King LE Jr. Nineteen documented cases of Loxosceles reclusa envenomation. J Am Acad Dermatol 2001;44:603-8.
4. Swanson DL, Vetter RS. Bites of brown recluse spiders and alleged necrotic arachnidism. N Engl J Med 2005 (in press).
5. Vetter RS, Isbister GK. Do hobo spider bites cause dermonecrotic injuries? Ann Emerg Med 2004 44:605-7.
Conflict of Interest:
None declared
-
Other Mimics of Infectious Cellulitis
Submit responseThe Editor Annals of Internal Medicine 190 N. Independence Mall West Philadelphia PA 19106-1572
To the Editor,
The review by Falagas and Paschalis on “Diseases That Masquerade as Infectious Cellulitis”(1) is a welcome compilation of many disorders that may be misdiagnosed or confused with infectious cellulitis. I would like to mention two additional conditions that are often misdiagnosed as infectious cellulitis:
The first is venous stasis dermatitis. This condition which is preceded by chronic venous insufficiency is a result of chronic edema and eventual extravasation of red blood cells into the dermis, resulting in signs of inflammation. When this condition ulcerates, secondary infection may occur. However, even when no ulceration exists, the condition may be manifest with signs of inflammation: pain, erythema, warmth and induration, although fever is generally not a component of this condition unless secondary infection has occurred.
The second is cutaneous expansion syndrome. This condition may result when edema from whatever cause occurs rapidly, expanding and stretching the surface of the skin. This is often present with erythema and mild warmth, mimicking mild cellulitis. The lack of fever and the often occurrence of this bilaterally is a clue against infectious origin.
Either of these conditions my result from venous thrombosis, which the authors discussed, but may often occur separately.
Sincerely,
Eric L. Westerman, M.D., F.A.C.P. Associate Professor of Medicine and Infectious Diseases Baylor College of Medicine Houston, Texas 77030 elw@bcm.tmc.edu
Conflict of Interest:
None declared
-
Submit response
Would not pyoderma gangrenosum, as sometimes seen in ulcerative colitis, qualify for inclusion in this category?