Leukoplakia: This condition is characterized by the formation of white patches or plaques on the mucous membranes, including the tongue. The presence of white ridges could be a variant of leukoplakia, especially if associated with chronic irritation or tobacco use.

Oral Lichen Planus: This is an autoimmune condition that can cause white, lacy patches on the tongue and other mucous membranes. It may also lead to the formation of white ridges.
Oral Candidiasis (Thrush): Although typically presenting with white patches that can be wiped off, chronic or recurrent candidiasis might lead to the formation of white ridges, especially in immunocompromised patients.
Nicotinic Stomatitis: Associated with heavy tobacco use, this condition can cause white patches and ridges on the tongue and palate due to chronic irritation.

Squamous Cell Carcinoma: Although less common, any unusual or persistent white lesion on the tongue should raise suspicion for oral cancer, especially in patients with risk factors like tobacco or alcohol use.
Lymphoma: Certain types of lymphoma can present with oral lesions, including white ridges or patches on the tongue, making it crucial to investigate further if other symptoms are present.

Pachyonychia Congenita: A rare genetic disorder that affects the nails and skin but can also cause white or thickened patches on the tongue.
White Sponge Nevus: A rare, benign condition that causes white, spongy patches on the mucous membranes, including the tongue, often inherited in an autosomal dominant pattern.
Darier's Disease: A rare genetic disorder that affects the skin and sometimes the mucous membranes, potentially causing white lesions or ridges on the tongue among other symptoms.