What causes itching in the labia majora skin without any lesions?

Causes of Itching in the Labia Majora Without Visible Lesions

The most common causes of vulvar itching without visible lesions are lichen sclerosus (which may be asymptomatic or in early stages), contact dermatitis/irritant reactions, iron deficiency, genitourinary syndrome of menopause (in postmenopausal women), and vulvovaginal candidiasis, with systemic causes like iron deficiency requiring investigation if local causes are excluded. 1, 2, 3

Primary Dermatologic Causes

Lichen Sclerosus (Early or Asymptomatic)

• Lichen sclerosus can be entirely asymptomatic and an incidental finding, or present with itch as the main symptom before visible lesions develop. 1
• When symptomatic, itch is often worse at night and may be severe enough to disturb sleep. 1
• The condition has a bimodal presentation with peaks in prepubertal girls and postmenopausal women. 1
• Early disease may not yet show the characteristic porcelain-white papules and plaques, making diagnosis challenging without biopsy. 1
• A confirmatory biopsy is advisable if there are atypical features or diagnostic uncertainty, though not always practical in children. 1

Contact Dermatitis and Irritant Reactions

• Environmental irritants are a major cause of vulvar pruritus, including detergents, soaps, cosmetics, and jewelry. 4, 5
• Treatment requires eliminating outside irritants and restoring epidermal barrier function. 5
• Contact dermatitis can cause inflammation without immediately visible lesions in early stages. 6

Vulvovaginal Candidiasis

• This is the most common infectious cause of vulvar pruritus and may present with itching before visible discharge or lesions appear. 2
• Topical or oral antimycotic drugs are the essential treatment. 2

Systemic Causes to Investigate

Iron Deficiency

• Iron deficiency is a well-established cause of generalized pruritus that can affect the vulvar area. 1, 7
• Ferritin levels should be checked in all cases of unexplained pruritus, especially where iron loss is suspected through diet (vegetarian/vegan) or potential blood loss. 1, 7
• Iron replacement can lead to complete cessation of pruritus shortly after treatment begins. 1, 7

Genitourinary Syndrome of Menopause

• In postmenopausal women, vulvovaginal atrophy is a common cause of itching without visible lesions. 3
• This should be considered in the appropriate age group even when examination appears normal. 3

Additional Systemic Causes (If Local Causes Excluded)

The British Association of Dermatologists recommends initial investigations for chronic pruritus including: 1, 7

• Full blood count and ferritin levels (iron deficiency) 1, 7
• Liver function tests (cholestatic disease) 1, 7
• Urea and electrolytes (chronic kidney disease) 1, 7
• Thyroid function tests if clinical features suggest thyroid disease 7
• HIV and hepatitis serology with appropriate risk history 7

Diagnostic Approach

When evaluating vulvar itching without lesions, first exclude local causes (irritants, candidiasis, early lichen sclerosus), then investigate systemic causes starting with iron studies. 1, 7, 2

Key History Elements

• Timing and severity of itch (worse at night suggests lichen sclerosus) 1
• Exposure to potential irritants (soaps, detergents, cosmetics, jewelry) 4, 5
• Dietary history (vegetarian/vegan diet suggesting iron deficiency) 1, 7
• Menopausal status (genitourinary syndrome of menopause) 3
• Sources of blood loss (menorrhagia, gastrointestinal symptoms) 1

Physical Examination Specifics

• Carefully inspect interlabial sulci, labia minora, clitoral hood, and perineum for subtle white changes or ecchymosis suggesting early lichen sclerosus. 1
• Assess for follicular delling or subtle hyperkeratosis. 1
• Check for signs of atrophy in postmenopausal women. 3

Treatment Algorithm

First-Line Symptomatic Management

• Eliminate all potential irritants (harsh soaps, perfumed products, tight clothing). 5
• Apply emollients and moisturizing care consistently. 8, 2
• Topical hydrocortisone can temporarily relieve external genital itching. 4
• Coolants like menthol may provide symptomatic relief. 8

Specific Treatments Based on Cause

• For lichen sclerosus: high-potency topical glucocorticoids 2
• For candidiasis: topical or oral antimycotic drugs 2
• For iron deficiency: iron replacement therapy 1, 7
• For genitourinary syndrome of menopause: appropriate hormonal therapy 3

Critical Pitfalls

• Do not assume absence of visible lesions excludes lichen sclerosus, as it may be asymptomatic or in early stages. 1
• Do not overlook iron deficiency as a systemic cause, particularly in women with dietary restrictions or blood loss. 1, 7
• Avoid prescribing prolonged courses of topical steroids without establishing a diagnosis, as this may delay recognition of serious conditions. 1
• In postmenopausal women, do not dismiss symptoms as simply "normal aging" without considering genitourinary syndrome of menopause. 3
• If pruritus persists despite adequate treatment, consider biopsy to exclude early neoplastic change or cutaneous lymphoma. 1, 7