Anorectal: Genital & perianal eczema

What is it?

Genital and perianal eczema is a common skin condition marked by itchy and inflamed patches of skin around the opening of the anus and the skin between the cheeks of the buttocks.

Most cases of eczema are diagnosed in childhood. It is often associated with an atopic tendency [Type I (IgE mediated) hypersensitivity reaction].

Eczema may be associated with asthma, allergic rhinitis, allergic conjunctivitis and food allergies.

Types of eczema (dermatitis)

• Contact dermatitis - dermatitis arising from direct skin exposure to an allergen or irritant
• Allergic dermatitis - an allergen induces an immune response upon re-exposure, after an initial sensitisation process (type IV hypersensitivity reaction)
  • Examples: perfume, latex, nickel, spermicide, topical antibiotics (neomycin), preservatives in creams
• Irritant dermatitis - substance causes direct physical, mechanical, or chemical skin irritation, usually on a repeated basis
  • Examples: soap, bleach, vigorous cleansing, shaving, sanitary pads, tight synthetic clothes, wetness, incontinence

Clinical presentation

Eczema is characterised by red, dry skin that flakes or forms scales, with occasional fissuring. It is typically itchy and/or burning.

Due to the moist environment, genital and perianal eczema often lacks superficial scale and may appear red and fissured:

• Acute - a rapidly evolving red rash that may be blistered and swollen, with a serous ooze or crusting
• Chronic - a longstanding irritated or scratched area which is often darker than the surrounding skin, with thickening of the skin layers (lichenification)

Management

• Identify and avoid the offending trigger
• Cold compresses may help relieve the itch
• Topical or oral steroids may be necessary depending on severity
• If there is an allergic component, an antihistamine may also be useful