**4.3 Lichen planus**

Chronic inflammatory disease can include dyskeratosis of the skin, oral and external genitalia mucosa. When it appears on the oral mucosa, lace or stitch pattern keratinizations

Dental Metal Allergy 95

oral mucosa close to the suspected dental prosthesis that contains the allergy-positive metal elements (Fig. 5). However, stomatitis and aphthous oral ulcers can sometimes occur on oral regions that are distant from the dental metal prosthesis. Regardless of the location,

In glossodynia, the main symptoms that patients encounter are pain, twitching and a burning sensation in the tongue. In some cases, no clear organic changes are ever found. Flare of the tongue, and an atrophy of the filiform papillae similar to that seen in geographical tongue can be found (Fig. 6). Possible predisposing factors include psychological factors, galvanic current, mechanical stimulation, allergy to metal elements

In generalized eczema, an intractable itching dermatitis occurs on all of the skin (Fig. 7). In 1965, Shanon (Shanon, 1965) first reported pseudoatopic dermatitis to be a general eczematoid dermatitis caused by a chromic allergy due to shoe leather and cement. The clinical findings for this type of dermatitis are exactly the same as those seen for atopic

recurrent formations of the inflammation are frequently observed in these cases.

eluted from a dental prosthesis, or a shortage of an essential nutrient.

**4.6 Generalized eczema and pseudoatopic dermatitis** 

Fig. 7. Generalized eczema and pseudoatopic dermatitis.

**4.5 Glossodynia** 

Fig. 6. Glossodynia.

may be present and accompanied by erosion and ulceration (Fig. 4). On the skin, red or purple-red papules are seen at the internal area of the joint extremities and trunk. While some of these papules may be painless, others can cause itch, heat sensation or pain.

The buccal mucosa is the favorite site of lichen planus. In longstanding cases, this keratinization pattern can sometimes spread into the entire oral mucosa. In dental metal allergy cases, it appears at the oral mucosa attached to the metal restoration that contains the allergy-positive metal element.

Histological findings exhibit parakeratosis, liquefaction degeneration of the basal cell, and T lymphocyte infiltration under the epithelial tissue. At the present time, the pathoetiology of lichen planus is still not clear. Mechanical stimulation, metal allergy, and the hepatitis C virus (HCV) are all suspected as being predisposing factors. Since Jubert et al. reported that about 30% of these patients exhibit HCV antibody, inveterate cases of lichen planus should have both liver function and HCV antibody tests performed.

Fig. 4. Lichen planus.
