Lichen Simplex Chronicus

Patients with LSC have single or multiple, well-demarcated lichenified plaque(s) that are slightly erythematous (early lesions) or hyperpigmented, and thickened (older lesions) with accentuation of the skin lines. LSC is typically seen on areas of skin that are easily reached to scratch such as the nape of the neck, scalp, external ear canals, upper back wrists, extensor forearms, ankles (Figs. 13.31 and 13.32), pretibial areas, or inner thighs. LSC may also involve the vulvae, scrotum (see Fig. 13.24), intragluteal area, and perianal area (pruritus ani).
Chronic or paroxysmal pruritus with scratching and rubbing is the primary symptom.

Differential Diagnosis in Genital Area

Tinea Cruris and Candidiasis (see Chapter 18: Superficial Fungal Infections)

A chronic itchy vulvar or scrotal rash may also suggest a fungal infection such as tinea cruris or candidiasis.
KOH examination or fungal culture is positive.

Inverse Psoriasis and Intertrigo (see Chapter 14: Psoriasis)

Should be considered when lesions involve the inguinal creases and perianal area.

Management

The most important aspect of therapy is the elimination of scratching and rubbing.
LSC may be treated with an intermediate-strength (class 3 or 4) topical corticosteroid, or if necessary, a high-potency (class 1) topical corticosteroid.
Occlusion, when required, has the added advantage of preventing patients from scratching or rubbing—or, at least, reminding them not to do so.
Oral antihistamines may be helpful at bedtime because of their sedative effect.
Protopic ointment (tacrolimus) 0.1% or Elidel cream 1% (pimecrolimus) may prove beneficial in patients with vulvar or perianal LSC.

Helpful Hint

There is a potential for stinging and burning when Protopic ointment is applied to sensitive, intertriginous (e.g., genital) areas. This can be lessened by refrigeration prior to its application.