Differential Diagnosis
- The patient's presentation of increasing discomfort in her finger after a prick while gardening, with no swelling, joint pain, or fever, suggests several possible diagnoses. The following categories outline the differential diagnosis:
Single most likely diagnosis
- Finger splinter or plant thorn injury: The patient's history of a prick while gardening and the removal of a small brown fleck, possibly a splinter, makes this the most likely diagnosis. The increasing discomfort is consistent with an infection or inflammation caused by the foreign body.
Other Likely diagnoses
- Infection (e.g., paronychia or cellulitis): Although the patient denies fever, a localized infection is possible, especially if the splinter or thorn introduced bacteria into the wound.
- Plant thorn dermatitis: Some plants, including roses, can cause a dermatitic reaction after a thorn prick, leading to discomfort and inflammation.
- Finger abscess: If the infection is localized and walled off, an abscess could form, causing increasing discomfort and potentially requiring drainage.
Do Not Miss (ddxs that may not be likely, but would be deadly if missed)
- Tetanus: Although rare, tetanus infection can occur after a puncture wound, especially if the wound is contaminated with soil or plant material. The patient's lack of fever and swelling does not rule out this diagnosis.
- Herpes simplex infection (herpetic whitlow): A herpetic infection can cause severe pain and discomfort in the finger, and although less likely, it is essential to consider this diagnosis to provide appropriate treatment.
Rare diagnoses
- Sporotrichosis: This fungal infection can occur after a puncture wound from a plant thorn, especially in gardeners. It typically causes a nodular lesion that can progress along the lymphatic channels.
- Actinomycosis: This rare bacterial infection can cause a chronic, granulomatous infection after a puncture wound, especially if the wound is contaminated with soil or plant material.
- Atypical mycobacterial infection: Similar to sporotrichosis, atypical mycobacterial infections can occur after a puncture wound from a plant thorn, causing a chronic infection that can be difficult to treat.