Sporotrichosis classification

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1] Associate Editor(s)-in-Chief: Alison Leibowitz [2]

Overview[edit | edit source]

Sporotrichosis may be classified, according to the location of the lesions, into particular subtypes: fixed cutaneous, lymphocutaneous, disseminated cutaneous, and extracutaneous/systemic. These subtypes may be further separated into increasingly specific forms based upon clinical manifestations.

Classification[edit | edit source]

• Presentations vary based upon numerous factors, such as the patient’s immunological status, the severity and depth of the inoculum, and the particular strain’s thermal zone of tolerance and pathogenicity.

Cutaneous Forms[edit | edit source]

Cutaneous forms of Sporotrichosis typically manifest following minor epidermal trauma. Patients may present with multiple forms of cutaneous lesions.

Fixed form:

• Staying localized within the subcutaneous tissue, the fungus transforms into its yeast form.
• Manifests at the site of inoculation with at least one, frequently ulcerated, lesion
• The lesions are characterized by red edges due to capillary dilation and congestion.
• Fixed form sporotrichosis may spontaneously regress ^[1]
• Fixed form sporotrichosis is the main clinical presentation in child patients.
• Initially manifests as painless nodules, which then become palpable, purulent, and ulcerated

Lymphocutaneous form:

• The yeast form of S. schenckii extends through the nearby lymphatic vessels.^[2]
• Approximately 70% of the cases of sporotrichosis may be classified as lymphocutaneous sporotrichosis.^[3]
• The primary lesion frequently manifests on the upper extremities and is initially painless.
• Initially a patient will present with a papule or pustule, which later expands into a subcutaneous nodule.^[3]
• Subepidermal pressure results in ischemia, and the lesion evolves into a palpable, purulent, and ulcerated nodule.
• Secondary lesions manifest along the adjacent lymphatic pathway.^[4]
• The presence of systemic symptoms is rare.

Disseminated cutaneous form:

• Manifests upon the hematogenous dissemination of the yeast form of S. schenckii
• Not associated with extracutaneous involvement
• Characterized by greater than or equal to three epidermal lesions, which form on at least two noncontiguous sites on the body

Mucosal Form:

• Typically manifests with enlargement of the submandibular and preauricular (anterior to ear tragus) lymph nodes
• Nasal mucosa is a variant of mucosal form sporotrichosis, which frequently involves septum lesions characterized by bloody discharge and crustal detachment.^[4]

Extracutaneous/Systemic Sporotrichosis[edit | edit source]

The extracutaneous forms of sporotrichosis are more likely to manifest following the onset of AIDS. These forms are uncommon and difficult to diagnose, but are almost always associated with immunological impairment^[4]

Osteoarticular form:[edit | edit source]

• Most common extracutaneous form of sporotrichosis
• Cutaneous lesions rarely manifest in cases of osteoarticular sporotrichosis.
• Usually starts as monoarticular disease without systemic illness
• May manifest by contiguity or hematogenous spread^[4]
• Characterized by the involvement of bones and joints
• Usually affects joints in the knee, wrist, elbow, and ankle
• May manifest with tenosynovitis or bursitis^[5]
• Frequently associated with arthritis
  • In these cases of coexisting diagnoses, lesions typically manifest along bones adjacent to affected joints. ^[6]

Primary pulmonary form:[edit | edit source]

• Patients present with primary pulmonary sporotrichosis following the inhalation of S. schenckii.
• Typically associated with alcoholism, chronic obstructive pulmonary disease, chronic corticosteroid use, and immunosuppressive diseases^[4]
• High risk of delayed diagnosis as a result of the rarity of pulmonary involvement in sporotrichosis manifestation and nonspecific symptoms

Disseminated form:[edit | edit source]

• Characterized by the involvement of at least two sites in the body
• Manifests as a result of hematogenic dissemination of S. schenckii, resulting in multifocal or widespread infection
• May initially manifest as another form of extracutaneous sporotrichosis
• Strongly associated with immunodeficiency

Other rare forms of sporotrichosis:

• endophthalmitis
• chorioretinitis

References[edit | edit source]