Sporotrichosis (rose gardener's disease): causes, symptoms and treatment

Sporotrichosis is an infection caused by fungi of the genus Sporothrix. UKHSA's risk statement, prepared by the Human Animal Infections and Risk Surveillance group, notes it is also known as rose gardener's disease, and that the fungus is found worldwide in soil and on plant and organic matter. Humans typically become infected through contact with fungal spores in contaminated environments, when the spores enter the skin through a penetrating injury.

There is no NHS patient information page for sporotrichosis, which reflects how uncommon it is in the UK. This page therefore draws mainly on UK Health Security Agency (UKHSA) documents and on DermNet NZ, a New Zealand dermatology reference, which is not a UK source.

UKHSA says most human cases result from exposure to fungal spores in the environment when they are inoculated through a penetrating lesion of the skin, and that gardening, horticulture, farming, fishing, hunting and mining may increase exposure. DermNet lists small cuts, scratches or punctures from thorns, barbs, pine needles or wires, and notes that sphagnum moss, hay and rose bushes are associated with infection.

Zoonotic transmission, from animals, is also recognised. UKHSA says it primarily occurs from bites, scratches or direct contact with secretions from lesions of infected animals, notably cats and, to a lesser extent, dogs. Veterinarians, pet shop workers and others working closely with cats may be at increased risk. In the UK, the only reported incident of zoonotic transmission so far was in 2022, when three people, two household contacts and a veterinarian, were infected from a cat imported from Brazil.

According to UKHSA, the average incubation period in humans is around 3 weeks, ranging from several days to 3 months. The most common presentation is the lymphocutaneous form. It typically begins as one or more reddish papules at the site where the fungus entered, develops into nodules under the skin, and spreads along the lymphatic channels, where it may ulcerate. General health is usually unaffected, but untreated lesions may persist for months or even years. The hands and arms are the most common sites.

DermNet describes the first sign as a firm bump that can range in colour from pink to nearly purple, usually painless or mildly tender, which gradually enlarges, reddens, becomes pustular and ulcerates, with further nodules developing in a line up the limb in a proportion of cases. Rarer forms can affect the lungs, bones and joints, or spread through the body, mostly in people with weakened immunity.

• A firm, painless or mildly tender lump on the hand, finger or forearm after a scratch or thorn injury.

• A sore that does not heal and may weep clear fluid.

• A chain of further lumps or sores running up the arm or leg.

• A history of cat scratches, especially from a cat imported from or living in South America.

See a GP about a sore or nodule that does not heal within a couple of weeks, especially if more lumps appear along the limb, if there is a cat scratch or bite, or if you have a weakened immune system. Tell the doctor about gardening, outdoor work, animal contact and any travel, because the history is what points towards the diagnosis. The UKHSA risk statement recommends that clinicians consider sporotrichosis early in cat owners with non-healing ulcers, with or without lymph node involvement, especially if there is a history of cat bites or scratches. Seek urgent help for fever with rapidly spreading redness, breathing problems, severe headache or confusion.

Other infections can look similar, so the diagnosis is confirmed by laboratory tests. DermNet explains that microscopy and culture of infected tissue identify Sporothrix and that skin biopsy can help. The UKHSA risk statement recommends that skin biopsies from a suspected human case are sent to UKHSA's National Mycology Reference Laboratory for fungal culture, histology with fungal staining and a pan-fungal PCR test. The UKHSA risk statement notes that diagnostic laboratories must report all positive Sporothrix samples to UKHSA under the Health Protection (Notification) Regulations 2010, although there is no duty for doctors to report suspected cases.

UKHSA says cutaneous and lymphocutaneous sporotrichosis usually respond well to antifungal drugs, with treatment given until all lesions have resolved, typically for 3 to 6 months. Disseminated disease requires a longer course for a year or more, and people with immunosuppressive conditions may require lifelong treatment to prevent recurrence. DermNet describes oral itraconazole for up to 6 months or oral terbinafine as options, with a traditional potassium iodide solution also used for skin disease.

The choice and length of treatment are decided by an infectious diseases, dermatology or microbiology specialist, who will also check for interactions and side effects. Completing the course matters because stopping early risks relapse.

DermNet advises wearing gloves, boots and clothing that covers the arms and legs when handling roses, hay bales, pine seedlings or sphagnum moss, and cleaning any scratch promptly. The UKHSA risk statement says veterinarians should take a travel history when seeing cats with unexplained lesions, that staff handling a suspected case should use protective equipment, and that contact between a person with the infection and their pet, or between an infected pet and its owner, should be minimised until treatment is finished and skin lesions have healed. It judges the risk of sporotrichosis from cats to the UK public to be very low at this stage.

Because it is rare, sporotrichosis is usually diagnosed after referral to dermatology or infectious diseases services, with samples sent to the national mycology reference laboratory. Private dermatology clinics can take biopsies but treatment of rarer fungal infections generally involves NHS specialist centres.