Sporotrichoid disorders, sometime also termed nodular lymphangitis, are defined as nodular abscesses that spread along lymphatics, away from a primary inoculation site. Streaking erythema, along lymphatics, may or may not be present. As the name implies, sporotrichosis is a fungal infection that serves as the prototype for the sporotrichoid presentation pattern.
Important History Questions
Have you had any recent injuries to your skin?
This is an important question because most sporotrichoid infections of the skin are associated with cutaneous inoculation injury. The classic (overrated) question is “Have you been working in a rose garden?” However, although rose gardening is a potential source of exposure for sporotrichosis, it is not the only way to acquire the infection.
Do you own cats, or have you been exposed to cats?
Cats are the animals most often infected with sporotrichosis, and the scratch of an infected cat can lead to infection. Veterinarians are at particular risk of this infection.
Have you had any fever or chills?
This is an attempt to gauge if there is any evidence of systemic infection.
Do you have any other medical problems?
This question can reveal important clinical information including whether the patient is immunocompromised.
Have you traveled outside of the United States?
Sporotrichosis and atypical mycobacterial infections are ubiquitous in the United States; nocardiosis is common in Mexico. Leishmaniasis requires travel to an endemic area for infection to develop.
Have you had a recent pedicure?
This is an important question if the patient has a suspected infection on the lower extremities, because pedicures represent an important source of mycobacterial infection.
Important Physical Findings
What is the distribution of the lesions?
Sporotrichoid infections are unilateral, unless disseminated, and follow a single lymphatic drainage basin. There are only rare exceptions to this rule, with the most common being atypical mycobacterial infections due to pedicures, in which bilateral exposure to contaminated water leads to bilateral infection.
Does there appear to be a lesion that represents a primary point of trauma?
The location of the primary lesion may suggest a potential diagnosis. Lesions on the hand are usually associated with gardening, which favors sporotrichosis. Lesions on the leg, especially in those who get pedicures, suggest a potential atypical mycobacterial infection. Such observations are useful in guiding empiric therapy while awaiting biopsy or culture results.
Are there any lesions outside of the lymphatic drainage basin?
Patients with sporotrichoid skin lesions may suffer dissemination, potentially with life-threatening systemic disease. Dissemination requires aggressive therapy, possibly with hospital admission and consultation with infectious disease specialists.
Sporotrichosis
ICD10 code B42.1
FUNGAL INFECTION
Pathogenesis
Sporotrichosis is due to a localized infection of the skin by the dimorphic fungus Sporothrix schenckii , a ubiquitous saprophytic fungus found in decaying vegetation (e.g., hay, sphagnum peat moss, wood, soil). The organism is found nearly worldwide, in temperate, subtropical, and tropical environs. The fungus is usually introduced into the skin via local injury, such as a thorn prick—hence, the classic question as to whether the patient works in a rose garden. Although many animal species can be infected, cats are notoriously susceptible and may infect humans directly by scratching. Although most sporotrichosis produces a sporotrichoid clinical pattern of infection (~80% of cases), fixed cutaneous infection (10%–15% of cases), disseminated infection, and pulmonary infection can also occur.
Clinical Presentation
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The initial lesion, usually found on extremities, especially the hand, is a tender erythematous papule that usually appears 1 to 3 weeks after the injury.
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The inoculation site often erodes or ulcerates or, more rarely, becomes verrucous or ulcerated.
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Secondary lesions consisting of erythematous nodules or abscesses appear along ascending lymphatics (nodular lymphangitis) en route to regional lymph nodes ( Figs. 18.1–18.3 ).
