Coccidioidomycosis (Valley fever): an imported fungal infection explained

Coccidioidomycosis is a fungal infection that primarily affects the lungs and respiratory tract, and in rare cases spreads to other parts of the body, according to DermNet NZ. It is also known as San Joaquin Valley fever, Valley fever or desert rheumatism. It is caused by soil fungi of the genus Coccidioides.

There is no NHS patient information page for coccidioidomycosis, because the infection is not acquired in the UK. This page draws on a UKHSA research-portal case report and the UKHSA Mycology Reference Laboratory's service description, together with DermNet NZ, a New Zealand dermatology reference which is not a UK source. Anyone with symptoms after travel should be assessed by a doctor.

Risk comes from time spent in an endemic area. DermNet lists travel to the south-western United States and parts of Mexico, Central and South America, outdoor occupations such as farming, construction and archaeology, pregnancy and immunocompromised status, including lymphoma, organ transplantation and treatment with TNF inhibitors, as risk factors, with higher incidence in late summer and early autumn.

The UK report describes a woman in her late sixties with rheumatoid arthritis and sarcoidosis treated with immunosuppressive agents, who had extensive travel to endemic countries. Her disseminated infection went undiagnosed for decades, which highlights that people on immunosuppressive treatment who have travelled to endemic areas are a group in whom the diagnosis should be considered.

DermNet says that mild or self-limiting infection presents with low-grade fever with chills and night sweats, fatigue, pain such as headaches, sore throat and chest pain, cough that may produce sputum or blood, loss of appetite and joint pain. Skin reactions such as erythema nodosum, tender red lumps on the shins, may appear about three weeks after the lung infection.

Disseminated disease involves spread of the lung infection to other organs, which DermNet says can involve soft tissues, joints, the central nervous system, eyes and the meninges, with altered mental status, lymph node enlargement, neck stiffness, swollen or stiff joints, light sensitivity and unexplained weight loss. The UK case involved a prosthetic knee joint infection with fever, chills, vomiting and joint pain.

• Fever, chills or night sweats weeks after returning from an endemic area.

• A persistent cough, chest pain or breathlessness.

• Joint pain or swelling, or tender red lumps on the shins.

• Severe headache, neck stiffness or confusion, which are emergencies.

Anyone who has been in an endemic area and develops a persistent cough, fever, night sweats or joint pain should see a GP and mention the travel, even if it was months or years earlier, because the UK case shows that the history can be forgotten. Call 999 or go to A&E for severe headache with stiff neck, confusion, seizures or severe breathing difficulty. People who are immunosuppressed should seek assessment sooner.

DermNet lists blood tests for antibodies, microscopy of sputum, PCR, culture and histology, and chest X-ray, with biopsies or lumbar puncture for suspected spread. In the UK, the UKHSA Mycology Reference Laboratory states that serology of non-indigenous mycoses, including coccidioidomycosis, is available, and that histology slides can be referred for examination. The UK case report notes that routine laboratory equipment may not be set up to detect the organism and that laboratories need to be told of the travel history, partly because of the occupational risk of handling Coccidioides in the laboratory.

DermNet says that for mild, self-limiting symptoms supportive care is most common, that fluconazole or itraconazole is used for moderate cases, and that posaconazole or amphotericin B are used for severe cases. It adds that treatment can go on for months or years and that in some patients lifelong suppression is needed. The UK case was treated with dual-antifungal therapy and remains on lifelong suppressive fluconazole.

Treatment decisions are made by infectious diseases or respiratory specialists, often with advice from the national reference laboratory. People who are immunosuppressed need particularly close follow-up.

No vaccine is described in the sources reviewed for this page. Avoiding dust exposure in endemic areas, particularly during dry, windy periods, digging, construction or dust storms, reduces risk, and travellers who are immunosuppressed should seek pre-travel advice from a travel clinic. DermNet does not list a specific prevention list, so this is general advice rather than something drawn from its page. The condition does not spread from person to person.

Imported fungal infections are managed in NHS infectious diseases and tropical medicine services, with samples sent to the national mycology reference laboratory. A travel clinic, NHS or private, can advise before a trip, and any doctor you see afterwards should be told where you have travelled.