Long-term drinking of very hot beverages can also cause a similar condition. The severity of the changes correlates with the frequency of the habit. The prevalence depends on a societys use of consuming hot beverages and of smoking in its various forms. A similar, but more pronounced palatal keratosis occurs with reverse smoking. This is where the lit end of the cigar or cigarette is held in the mouth, another form of smoking associated with high levels of heat in the mouth. This form of the condition is sometimes termed "reverse smokers keratosis", and is a premalignant lesion. That is, the condition is associated with an increased risk of malignant transformation to oral squamous cell carcinoma (a type of oral cancer). Some sources do not distinguish between reverse smokers keratosis and smokers palate that is caused by heat. As such, these sources tend to state that stomatitis nicotina is a premalignant condition. Some reports show that there is an increased risk of tonsillar cancer, lung cancer and tumors of the posterior oral cavity in people who develop stomatitis nicotina. Diagnosis
The diagnosis is normally made based upon the clinical appearance and history. Tissue biopsy is not usually indicated unless there are areas of ulceration or localized erythroplakia (red patches). The differential diagnosis is with other causes of white lesions (see leukoplakia for a more complete discussion).
Specific conditions which can produce a similar appearance include Dariers disease, discoid lupus erythematosus, oral candidiasis, and oral lichen planus.If a biopsy is taken, the histopathologic appearance is one of hyperkeratosis and acanthosis. There may be squamous metaplasia of excretory ducts, which results in the visible papules if the ducts become hyperplastic. Neutrophils may fill some ducts. It is characterized as a "fissured" or "dried mud" appearance from excess keratin production by cells. Dysplasia is rarely seen. Treatment
When the appearance is caused by heat, the lesion is usually completely reversible within a few weeks if the smoking habit is stopped. This is the case even if the condition has been present for decades. Without stopping smoking, spontaneous remission of the lesion is unlikely. If the lesion persists despite stopping smoking, this is usually then considered to be a true leukoplakia rather than a reactionary keratitis, and may trigger the decision to carry out a biopsy to confirm the diagnosis. Since this condition almost always develops in the setting of long term heavy smoking, it usually indicates the need for regular observation for cancers associated with smoking, e.g. lung cancer. Epidemiology
The condition is uncommon. It occurs usually in elderly males who have a history of heavy pipe smoking, but it also can occur in cigar or cigarette smokers. The condition was once common, but has become more rare as habits such as pipe and cigar smoking have decreased in popularity. See also
Smokers melanosis
Smokeless tobacco keratosis

References

Kahn, Michael A. Basic Oral and Maxillofacial Pathology. Volume 1. 2001.