๐ ็ธฝ็ฎ้ ๏ฝ ๐ ่ฑๆๅๆ๏ผๆฌ็ฏ๏ผ ๏ฝ ๐ ๅฎๆด็ฟป่ญฏ ๏ฝ โญ ็ฒพ่ฏ็ญ่จ
LICHEN SIMPLEX CHRONICUS (LSC)
LICHEN SIMPLEX CHRONICUS (LSC)ย ย ICD-10: L28
โข A special localized form of lichenification, occurring in circumscribed plaques.
โข Occurs in individuals older than 20 years, is more frequent in women, and possibly more frequent in Asians.
โข Results from repetitive rubbing and scratching.
โข Skin symptoms consist of pruritus, often in paroxysms, when the rubbing becomes automatic and reflexive, like an unconscious habit.
โข Lichenification is a characteristic feature of AD, whether generalized or localized.
โข A solid plaque of lichenification, arising from the confluence of small papules (Fig. 2-18). Skin is palpably thickened; skin markings (barely visible in normal skin) are accentuated and can be readily seen. Excoriations. Usually sharply defined. Isolated single lesion or several plaques. Nuchal area (female) (Fig. 2-18), scalp, ankles, lower legs, upper thighs, exterior forearms, vulva, pubis, anal area, scrotum, and groin. In African American and dark skin tones, lichenification may assume a special type of pattern consisting of multiple small (2 to 3 mm) closely set papules, a โfollicularโ pattern (as in Fig. 2-14B).
โข Lichen simplex chronicus can last for decades unless the rubbing and scratching are stopped by treatment.
โข Differential diagnosis includes a chronic pruritic plaque of psoriasis vulgaris, early stages of mycosis fungoides, ICD, ACD, and epidermal dermatophytosis.
โข Management Difficult. Explain to the patient that rubbing and scratching must be stopped. Occlusive bandages can be used. Topical glucocorticoid preparations or tar preparations covered by occlusive dressings; if left for 24 h, glucocorticoids incorporated in adhesive plastic tape are also effective.
โข Intralesional triamcinolone is often highly effective in smaller lesions (3 to 5 mg/mL; higher concentrations may cause atrophy). Oral hydroxyzine, 25 to 50 g at night, may be helpful.
FIGURE 2-18 โข Lichen simplex chronicusโConfluent, papular, follicular eczema, creating a plaque of lichen simplex chronicus of the posterior neck and occipital scalp. The condition had been present for many years as a result of chronic rubbing of the area.