11 Lichen simplex (also sometimes called lichen simplex chronicus) should not be confused with lichen sclerosus or lichen planus. It is a distinct entity that results from chronic scratching and rubbing an area of skin. It is seen at sites that are easily accessible to the patient such as the occipital scalp and lower limb, but the ano‐genital skin is frequently affected. Vulval lichen simplex mainly occurs in young and middle‐aged women. It can start in childhood but is not common in this age group. The incidence of vulval lichen simplex is not known but it is a common condition and accounts for 10–35% of patients seen in vulval clinics. In a series of 183 vulval biopsies of dermatoses, 29% showed changes of lichen simplex. Lichen simplex tends to occur in patients who have a background of eczema or psoriasis, particularly atopic eczema. Rarely, it can occur secondary to fungal infection or other dermatoses and these may not be immediately obvious when the lichenification is severe. In some cases, there is no obvious reason why the pruritus has started. Some authors refer to this group as primary lichen simplex. The role of psychological factors has been postulated and these are important in some patients who may relate the onset of their symptoms to a stressful event. Lichen simplex is characterized by hyperkeratosis with thickening and elongation of the epidermal ridges. A dermal inflammatory cell infiltrate is usually present and papillary dermal fibrosis is typical. The symptom is intense itching, which gradually worsens over months and years. Both the vulva and perianal skin can be affected but patients commonly describe vulval pruritus initially, which then spreads to the perianal skin. Premenstrual exacerbation of symptoms is common. As there is no scarring or architectural change in lichen simplex, it rarely causes any difficulties with intercourse. The itch is intense and patients may wake at night scratching. During the day, the itch may not be so severe but they will often admit to vigorous scratching, which can help their symptoms. Some will scratch until the skin breaks and the sensation of itch is then replaced by discomfort. The architecture of the vulva is normal. The major areas affected are the outer labia majora, which become thickened (Figure 11.1
Lichen Simplex
Introduction
Epidemiology
Incidence
Pathophysiology
Histological features
Symptoms
Clinical features
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