Sporotrichosis

A fungal infection commonly known as "rose gardener's disease" caused by the Sporothrix fungus

Table of Contents

Overview

Sporotrichosis is a chronic fungal infection caused by Sporothrix schenckii, a fungus commonly found in soil, plants, and decaying vegetation. Often called "rose gardener's disease," this infection typically occurs when the fungus enters the body through small cuts or punctures in the skin. While sporotrichosis most commonly affects the skin and lymphatic system, it can occasionally spread to other parts of the body, including bones, joints, and rarely, the lungs or central nervous system.

The disease has a worldwide distribution but is more common in tropical and subtropical regions. It primarily affects people who handle thorny plants, sphagnum moss, hay, or soil in their occupations or hobbies. Gardeners, nursery workers, farmers, and florists are at higher risk. The infection is not contagious and cannot spread from person to person, except in very rare cases of direct inoculation.

Sporotrichosis presents in several clinical forms, with the lymphocutaneous form being the most common, accounting for about 75% of cases. The infection typically progresses slowly, and while it rarely causes life-threatening illness in healthy individuals, it can be more severe in people with weakened immune systems. Early recognition and treatment are important to prevent the spread of infection and potential complications.

Symptoms

The symptoms of sporotrichosis vary depending on the form of the disease and the site of infection. The incubation period typically ranges from 1 to 12 weeks after exposure, with most cases developing symptoms within 3 weeks.

Cutaneous (Skin) Form

The most common presentation, affecting the skin at the site of injury:

  • Small, painless bump (nodule) at the infection site
  • Pink, red, or purple coloration of the nodule
  • Gradual enlargement and ulceration
  • Slow-healing open sore
  • Usually on hands, arms, or fingers

Lymphocutaneous Form

The infection spreads along lymphatic channels:

  • Initial nodule as in cutaneous form
  • Development of additional nodules along lymphatic vessels
  • Linear pattern of nodules moving up the arm or leg
  • Nodules may ulcerate and drain
  • Usually painless unless secondarily infected
  • Swollen lymph nodes

Disseminated Sporotrichosis

Rare but serious form affecting multiple body sites:

  • Joint pain and swelling (osteoarticular involvement)
  • Wrist pain - common site of joint involvement
  • Knee pain - another frequent joint affected
  • Bone pain
  • Weight loss
  • Fever (in severe cases)
  • Fatigue

Pulmonary Sporotrichosis

Rare form affecting the lungs:

  • Chronic cough
  • Shortness of breath
  • Chest pain
  • Blood in sputum (hemoptysis)
  • Weight loss
  • Night sweats

Associated Symptoms

  • Regional lymphadenopathy
  • Secondary bacterial infection of ulcers
  • Scarring at healed sites
  • Chronic drainage from lesions

Causes

Sporotrichosis is caused by fungi in the Sporothrix schenckii complex, which includes several closely related species. Understanding the source and transmission of this fungus is crucial for prevention.

The Causative Organism

  • Sporothrix schenckii sensu stricto - Most common species globally
  • Sporothrix brasiliensis - Common in Brazil, more virulent
  • Sporothrix globosa - Found in Asia and Europe
  • Sporothrix mexicana - Found in Mexico

Environmental Sources

The fungus is naturally found in:

  • Soil and decaying vegetation
  • Rose bushes and thorns
  • Sphagnum moss
  • Hay and straw
  • Tree bark and branches
  • Garden mulch

Mode of Transmission

Traumatic Inoculation

  • Puncture wounds from thorns or splinters
  • Cuts or abrasions contaminated with soil
  • Minor trauma while handling contaminated materials
  • Scratches from infected animals (especially cats in Brazil)

Inhalation (Rare)

  • Breathing in fungal spores
  • Can lead to pulmonary sporotrichosis
  • More likely in immunocompromised individuals

Zoonotic Transmission

In some regions, particularly Brazil:

  • Cat-to-human transmission through scratches or bites
  • Infected cats can have numerous lesions with high fungal burden
  • Veterinarians and pet owners at increased risk
  • Dog-to-human transmission is less common

Host Factors

  • Breach in skin integrity required for infection
  • Local trauma facilitates fungal entry
  • Immune status affects disease progression
  • Temperature preference of fungus (grows best at 25-30°C)

Risk Factors

Certain occupations, activities, and health conditions increase the risk of developing sporotrichosis.

Occupational Risk Factors

  • Gardeners and landscapers - Frequent contact with roses and thorny plants
  • Nursery workers - Handle various plants and soil
  • Farmers - Exposure to hay, straw, and soil
  • Florists - Work with roses and other plants
  • Forest workers - Contact with tree bark and moss
  • Laboratory workers - Handling fungal cultures
  • Veterinarians - In endemic areas with zoonotic transmission

Recreational Activities

  • Rose gardening
  • Handling sphagnum moss
  • Working with hay bales
  • Collecting or arranging dried flowers
  • Outdoor activities in endemic areas

Geographic Risk Factors

  • Tropical and subtropical regions - Higher prevalence
  • Areas with high humidity - Favorable for fungal growth
  • Specific endemic regions - Peru, Brazil, Mexico, Japan
  • Rural areas - Greater environmental exposure

Immunocompromising Conditions

Increase risk of severe or disseminated disease:

  • HIV/AIDS
  • Diabetes mellitus
  • Chronic alcoholism
  • Organ transplant recipients
  • Cancer patients on chemotherapy
  • Long-term corticosteroid use
  • Primary immunodeficiency disorders

Other Risk Factors

  • Male gender (higher occupational exposure)
  • Age 30-60 years (peak occupational exposure)
  • Poor wound care practices
  • Lack of protective equipment
  • Contact with infected animals in endemic areas

Diagnosis

Diagnosing sporotrichosis requires a combination of clinical suspicion, laboratory testing, and sometimes histopathological examination. Early diagnosis is important for appropriate treatment.

Clinical Evaluation

History Taking

  • Occupational or recreational exposure
  • Recent gardening or plant handling
  • Timeline of lesion development
  • Geographic location and travel history
  • Animal contact, especially cats
  • Immunosuppressive conditions

Physical Examination

  • Characteristic nodular lesions
  • Linear distribution along lymphatics
  • Absence of significant pain
  • Regional lymphadenopathy
  • Assessment for disseminated disease

Laboratory Diagnosis

Fungal Culture

  • Gold standard for diagnosis
  • Culture of pus, tissue, or exudate
  • Growth on Sabouraud dextrose agar
  • Characteristic colony morphology
  • Temperature dimorphism testing
  • May take 2-4 weeks for growth

Direct Microscopy

  • KOH preparation of specimens
  • Often negative due to low fungal burden
  • May show cigar-shaped yeast cells
  • Special stains (PAS, GMS) improve visualization

Histopathology

  • Skin biopsy showing granulomatous inflammation
  • Asteroid bodies (Splendore-Hoeppli phenomenon)
  • Fungal elements may be scarce
  • Special stains required

Molecular Diagnosis

  • PCR - Species identification
  • DNA sequencing - Definitive species identification
  • MALDI-TOF MS - Rapid identification

Serological Tests

  • Limited availability and utility
  • Antibody detection assays
  • May help in disseminated cases
  • Cross-reactions possible

Differential Diagnosis

Conditions to consider:

  • Cutaneous leishmaniasis
  • Nocardiosis
  • Atypical mycobacterial infections
  • Cutaneous tuberculosis
  • Pyoderma gangrenosum
  • Other deep fungal infections

Treatment Options

Treatment of sporotrichosis depends on the clinical form, extent of disease, and patient's immune status. Most cases respond well to appropriate antifungal therapy.

First-Line Treatment

Itraconazole

  • Drug of choice for lymphocutaneous and cutaneous forms
  • Typical dose: 200 mg daily
  • Duration: 3-6 months
  • Continue for 2-4 weeks after clinical cure
  • Monitor liver function
  • Check drug interactions

Alternative Treatments

Saturated Solution of Potassium Iodide (SSKI)

  • Traditional treatment still used in some regions
  • Start with 5 drops three times daily
  • Gradually increase to 40-50 drops three times daily
  • Mix with juice or milk
  • Side effects: metallic taste, GI upset, rash
  • Contraindicated in pregnancy and thyroid disease

Terbinafine

  • Alternative for cutaneous forms
  • Dose: 250 mg twice daily
  • May be less effective than itraconazole
  • Consider for itraconazole intolerance

Treatment of Severe Forms

Amphotericin B

  • For severe or disseminated disease
  • Initial therapy in life-threatening cases
  • Lipid formulations preferred
  • Switch to oral therapy when stable
  • Monitor renal function and electrolytes

Combination Therapy

  • May be needed for refractory cases
  • Itraconazole plus terbinafine
  • Consider in immunocompromised patients

Local Treatment

  • Thermotherapy - Local heat application
  • Cryotherapy - For limited cutaneous lesions
  • Surgical excision - Small, localized lesions
  • Intralesional amphotericin B - Selected cases

Supportive Care

  • Wound care for ulcerated lesions
  • Pain management if needed
  • Treatment of secondary bacterial infections
  • Nutritional support
  • Management of underlying conditions

Monitoring and Follow-up

  • Regular clinical assessment
  • Monitor for treatment response
  • Check for adverse drug effects
  • Ensure completion of therapy
  • Watch for recurrence

Prevention

Preventing sporotrichosis involves minimizing exposure to the fungus and protecting the skin from injury when handling potentially contaminated materials.

Personal Protective Equipment

  • Wear heavy-duty gloves when gardening
  • Use long sleeves and pants
  • Wear closed-toe shoes
  • Consider protective eyewear
  • Use arm guards when pruning roses

Safe Gardening Practices

  • Handle roses and thorny plants carefully
  • Avoid working with sphagnum moss with bare hands
  • Clean and cover any cuts or scratches immediately
  • Wash hands thoroughly after gardening
  • Dispose of plant debris properly
  • Keep tetanus vaccination up to date

Occupational Safety

  • Employer-provided protective equipment
  • Safety training for at-risk workers
  • First aid supplies readily available
  • Prompt wound care protocols
  • Regular health monitoring

Environmental Measures

  • Minimize skin contact with soil
  • Store hay and straw in dry conditions
  • Control moisture in work environments
  • Proper ventilation in enclosed spaces
  • Regular cleaning of gardening tools

Animal-Related Prevention

In areas with zoonotic transmission:

  • Treat infected cats promptly
  • Wear gloves when handling sick animals
  • Avoid scratches and bites
  • Educate pet owners about risks
  • Veterinary surveillance programs

High-Risk Individuals

Special precautions for immunocompromised persons:

  • Avoid high-risk activities if possible
  • Extra vigilance with protective measures
  • Prompt medical attention for any skin injury
  • Consider prophylaxis in some cases
  • Regular skin examinations

When to See a Doctor

Early medical evaluation is important for proper diagnosis and treatment of sporotrichosis.

Seek Medical Attention If You Have:

  • A non-healing skin sore after plant injury
  • Nodules developing along the arm after gardening
  • Skin lesions that persist for more than 2 weeks
  • Multiple bumps in a line pattern
  • Ulcers that drain and don't heal
  • Joint pain and swelling after skin injury
  • Suspected exposure with compromised immunity

Urgent Evaluation Needed For:

  • Signs of disseminated infection
  • High fever with skin lesions
  • Shortness of breath or cough
  • Confusion or neurological symptoms
  • Severe joint pain and swelling
  • Weight loss with chronic lesions

Information to Provide Your Doctor:

  • Recent gardening or outdoor activities
  • Contact with roses or thorny plants
  • Handling of moss, hay, or mulch
  • Timeline of symptom development
  • Any animal scratches or bites
  • Travel to endemic areas
  • Underlying health conditions

Frequently Asked Questions

Is sporotrichosis contagious between people?

No, sporotrichosis typically does not spread from person to person. The fungus must enter through a break in the skin to cause infection. Very rare cases of transmission have occurred through accidental inoculation in laboratory or healthcare settings. However, in areas where cat-transmitted sporotrichosis occurs, infected cats can transmit the disease to humans through scratches or bites.

How long does treatment for sporotrichosis take?

Treatment duration varies depending on the form and severity of infection. For cutaneous and lymphocutaneous forms, treatment typically lasts 3-6 months. The medication is usually continued for 2-4 weeks after all lesions have healed to prevent recurrence. Disseminated or severe cases may require longer treatment, sometimes up to 12 months or more.

Can sporotrichosis come back after treatment?

Recurrence is uncommon if treatment is completed as prescribed. However, reinfection can occur with new exposure to the fungus. People who continue to work with plants or soil remain at risk. Immunocompromised individuals have a higher risk of recurrence and may need longer treatment or maintenance therapy.

Why is it called rose gardener's disease?

Sporotrichosis got this nickname because many cases occur in people who handle roses. The thorns create puncture wounds that allow the fungus to enter the skin. The fungus lives in soil and on plant matter, including rose bushes. However, many other activities involving plants, soil, or organic matter can also lead to infection.

Can sporotrichosis affect internal organs?

Yes, but this is rare in healthy individuals. Disseminated sporotrichosis can affect bones, joints, lungs, and rarely the central nervous system. This is more likely to occur in people with weakened immune systems, such as those with HIV/AIDS, diabetes, or those taking immunosuppressive medications. Early treatment of skin infections helps prevent dissemination.

References

  1. Chakrabarti A, et al. Global epidemiology of sporotrichosis. Med Mycol. 2015;53(1):3-14.
  2. Orofino-Costa R, et al. Sporotrichosis: an update on epidemiology, etiopathogenesis, laboratory and clinical therapeutics. An Bras Dermatol. 2017;92(5):606-620.
  3. Kauffman CA, et al. Clinical practice guidelines for the management of sporotrichosis: 2007 update by the Infectious Diseases Society of America. Clin Infect Dis. 2007;45(10):1255-65.
  4. Mahajan VK. Sporotrichosis: an overview and therapeutic options. Dermatol Res Pract. 2014;2014:272376.
  5. Centers for Disease Control and Prevention. Sporotrichosis. Updated 2023.
  6. Barros MB, et al. Sporotrichosis: an emergent zoonosis in Rio de Janeiro. Mem Inst Oswaldo Cruz. 2011;106(6):664-7.