๐ ็ธฝ็ฎ้ ๏ฝ ๐ ่ฑๆๅๆ๏ผๆฌ็ฏ๏ผ ๏ฝ ๐ ๅฎๆด็ฟป่ญฏ ๏ฝ โญ ็ฒพ่ฏ็ญ่จ
Talc
Talc (hydrous magnesium silicate) is a common cause of foreign body granulomas given its presence in dusting, antifungal, and antibiotic powders. In addition, it is still preferred by some surgeons as a lubricant for surgical gloves. Talc can therefore contaminate wounds, erosions, and umbilical stumps, or it may enter the skin via abrasions and fissures, particularly in intertriginous zones in obese individuals who apply talc powder liberally.
Individuals with substance use disorder who inject solutions intravenously or subcutaneously that contain crushed tablets may also develop foreign body reactions to talc as talc is a common filler in tablets. The foreign body reactions may arise at injection sites or at distant sites (e.g. pulmonary intravascular talcosis).
Clinical features
As with reactions to other forms of silica, the lesions usually take a long time to appear. The clinical appearance is varied: it may take the form of erythematous papules and nodules or simply thickening and erythema of an old scar, similar to the range of findings in sarcoidosis. Rarely lesions may resemble a pyogenic granuloma. Despite the long latency period, the diagnosis should be considered, especially when lesions appear in certain sites, e.g. the umbilicus in infants, inguinal area in patients with a history of intertrigo, injection sites in those with a history of intravenous drug use.
Pathology
The histologic features may be similar to those of sarcoidosis or non-caseating tuberculosis. Alternatively, there may be granulomatous inflammation consisting of histiocytes and foreign body giant cells. A few of these cells may contain clear, blueโgreen, or yellowโbrown, needle-shaped or round crystals. Under polarized light, talc crystals are birefringent. A picture simulating a pyogenic granuloma plus giant cells has also been described.
Treatment
Excision of persistent symptomatic lesions is recommended.