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← Dermatology indexChapter sections
OverviewAetiologyPathophysiologyClinical features and red flagsInvestigationsDifferential diagnosisManagementComplicationsMonitoring and follow-upSpecial situationsCommon pitfallsQuestionsSources
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Educational draft · awaiting clinical reviewThe full textbook explains uncertainty but does not replace live national or local guidance, specialist advice, or current prescribing information.

Bowen disease

Dermatology · UK scope · Sources checked 27 Aug 2026 · Clinical review pending

RapidFull

Overview

Recognise cutaneous squamous-cell carcinoma in situ, distinguish it from eczema, psoriasis and invasive SCC, secure histology when needed and select treatment by site, lesion and patient factors.

Bowen disease remains confined to epidermis but is malignant. Record duration, growth, symptoms, previous treatments, immune state and carcinogen exposure. Examine the full plaque for a focal nodule or ulcer and the surrounding field for other cancers. A chronic scaly plaque repeatedly labelled eczema deserves histology when it remains solitary and treatment resistant.

Treatment balances cure with healing. Excision provides complete histology and is useful where invasion is possible. Curettage, cryotherapy, photodynamic therapy and topical 5-fluorouracil can treat selected in-situ lesions. Lower-leg skin with venous disease may tolerate non-surgical care better, yet large or recurrent plaques may still require specialist surgery.

Field reactions need anticipatory counselling. Fluorouracil is applied to a precisely mapped lesion and expected to cause erythema and erosion. The clinical endpoint is durable clearance after healing, not maximal inflammation. New firmness or ulceration during or after therapy needs review for previously unrecognised invasion.

Key points

  • Bowen disease is SCC in situ: a persistent, slowly enlarging, well-demarcated scaly or crusted plaque, commonly on sun-exposed lower legs.
  • Colour may be pink-red, violaceous or brown and is less reliable than persistent single-site scale and edge definition across skin tones.
  • Biopsy when diagnosis is uncertain and whenever pain, induration, ulceration, bleeding or treatment resistance suggests invasion.
  • Treatment options include excision, curettage and cautery, cryotherapy, photodynamic therapy and topical 5-fluorouracil; imiquimod is often off label.
  • Choice depends on size, site, number, border, circulation, healing capacity, immune state, pathology and patient preference.
  • Lower-leg lesions require vascular and oedema assessment because destructive or surgical wounds may heal slowly.
  • A genital or periungual lesion needs specialist assessment for HPV association, functional anatomy and alternative malignancy.
  • After treatment, review for clinical clearance and biopsy a persistent thick or ulcerated focus instead of repeating empirical therapy.

Aetiology

01

Ultraviolet damage

Cumulative ultraviolet injury is the principal driver on exposed lower legs, head, neck and hands, reflecting broader field cancerisation.

02

Immune suppression

Solid-organ transplantation, haematological malignancy and sustained immunosuppressive therapy increase lesion multiplicity, treatment recurrence and invasive progression risk.

03

Human papillomavirus

Oncogenic HPV contributes particularly to genital, periungual and selected non-sun-exposed lesions and changes their sexual-health and immune context.

04

Other carcinogens

Previous arsenic exposure, therapeutic radiotherapy, chronic skin injury and inherited genetic susceptibility account for a minority of presentations.

Pathophysiology

  1. 1
    Full-thickness epidermal dysplasia

    Atypical keratinocytes occupy the entire epidermis but remain above the basement membrane, defining SCC in situ.

  2. 2
    Slow lateral expansion

    Dysplastic clones spread across epidermis, producing a persistent sharply demarcated scaly plaque that enlarges over months or years.

  3. 3
    Surface keratin and inflammation

    Disordered maturation creates crust and scale, while inflammation causes itch and variable red, violaceous or brown colour.

  4. 4
    Invasive transformation

    Basement-membrane breach creates dermal SCC, often signalled by focal thickening, pain, ulceration, bleeding or accelerated growth.

Clinical features and red flags

Fixed scaly plaque

A sharply demarcated irregular plaque remains at one site and enlarges slowly despite routine eczema care.

Crusted uneven surface

Scale, crust and shallow erosion vary across the lesion while the border remains clinically definable.

Pigmented Bowen disease

Brown or black in-situ SCC can mimic melanoma or pigmented BCC and requires dermoscopic and histological assessment.

Invasive focusRed flag

A new firm nodule, pain, ulcer, spontaneous bleeding or rapid growth within the plaque suggests SCC invasion.

High-consequence site

Genital, nail-unit, lip or ear disease has diagnostic, functional and HPV-related complexity needing specialist care.

Red flags requiring action

  • New induration, nodule, tenderness, ulceration, bleeding, rapid growth, failure after appropriate treatment, lip or genital site, immune suppression or palpable nodes raises invasive SCC and requires urgent specialist biopsy.

Investigations

  1. 01
    Punch or incisional biopsyFirst step
    Why
    Confirm full-thickness epidermal dysplasia and assess possible invasion.
    Interpretation and limitations
    Target the thickest, firmest or ulcerated area and include dermis; a superficial scale sample cannot exclude SCC.
  2. 02
    Dermoscopy
    Why
    Support recognition and distinguish vascular, keratin and pigment patterns from common mimics.
    Interpretation and limitations
    Dotted or glomerular vessels may support Bowen disease but histology determines invasion.
  3. 03
    Vascular and oedema assessment
    Why
    Predict healing risk before lower-leg surgery or destructive treatment.
    Interpretation and limitations
    Assess pulses and symptoms and use ABPI when compression or arterial uncertainty makes it relevant.
  4. 04
    Histological margin review
    Why
    Confirm clearance after excision and identify occult invasive disease.
    Interpretation and limitations
    Involved margins, invasion or aggressive features return to the skin-cancer multidisciplinary pathway.

Differential diagnosis

01

Eczema

Dermatitis is often multiple, itchy, less sharply fixed and responsive to appropriate corticosteroid, while Bowen persists at one site.

02

Psoriasis

Symmetrical plaques, scalp or extensor disease and nail pitting support psoriasis, though an isolated resistant plaque needs biopsy.

03

Superficial basal-cell carcinoma

A thin superficial BCC may have a thread-like pearly edge and dermoscopic arborising vessels or pigmented leaf-like structures.

04

Invasive SCC

New induration, a growing nodule, pain, ulceration or spontaneous bleeding suggests dermal invasion and changes urgency and treatment.

05

Tinea corporis

An advancing scaly edge and central clearing supports dermatophyte infection; scraping can prevent steroid or cancer-treatment error.

Management

01Confirmed suitable in-situ lesionSelect site-conscious treatmentFirst stepHistology or confident specialist assessment confirms Bowen disease without invasive warning.+
  1. 1Assess size, site, border, circulation, healing, immune state and the patient’s priorities.
  2. 2Choose excision, curettage, cryotherapy, photodynamic therapy or a mapped topical course according to local expertise.
  3. 3Review after healing for complete clinical clearance and provide long-term skin-cancer awareness advice.
02Possible invasionBiopsy the changing focusPain, induration, nodule, ulceration, bleeding or accelerated growth appears.+
  1. 1Stop empirical field treatment and document the suspicious focus, nodes and immune state.
  2. 2Arrange urgent adequate-depth biopsy or excision and route invasive SCC through the cancer pathway.

Complications

01

Invasive SCC

A minority of lesions progress through the basement membrane and acquire clinically important local destructive and metastatic potential.

02

Recurrence

Large, poorly defined, immune-suppression-associated or incompletely treated plaques can return after apparent clearance and may conceal invasive foci.

03

Treatment ulceration

Lower-leg surgery, cryotherapy and field inflammation can heal slowly where oedema or arterial disease impairs repair.

04

Multiple keratinocyte cancers

Bowen disease marks substantial cumulative carcinogenic exposure and predicts further actinic keratoses, invasive SCC and basal-cell carcinoma.

Monitoring and follow-up

  • Review topical-treatment inflammation when clinically needed and assess clearance only after epithelial healing.
  • Palpate treated skin for residual induration and biopsy persistent scale, nodule or ulcer.
  • Monitor lower-leg wounds closely where venous oedema, diabetes or arterial disease delays repair.
  • Continue whole-skin surveillance proportional to immune state, field damage and previous cancers.
  • Safety-net new pain, bleeding, rapid growth or a regional node for urgent reassessment.

Special situations

In situ is still cancer

Basement membrane containment removes metastatic capability but not the need for definitive treatment and follow-up.

One eczema patch deserves thought

A solitary fixed treatment-resistant plaque is less typical of ordinary relapsing dermatitis and may need biopsy.

Lower legs heal differently

Venous oedema and limited arterial supply can make an otherwise simple destructive treatment produce a chronic wound.

Thickness changes urgency

A new indurated focus within a flat plaque is more concerning than widespread stable surface scale.

Common pitfalls

  1. 01

    Prescribing repeated topical steroid for one persistent scaly plaque without securing diagnosis.

  2. 02

    Using superficial biopsy and failing to sample an indurated focus deeply enough for invasion.

  3. 03

    Choosing lower-leg surgery without assessing vascular and oedema-related healing risk.

  4. 04

    Assuming a vigorous fluorouracil reaction proves histological clearance.

  5. 05

    Retreating a recurrent ulcerated plaque without excluding invasive SCC.

Practice

Two practice questions

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Question 1 of 2
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DermatologyOriginal SBA

Solitary treatment-resistant plaque

A slowly enlarging sharply demarcated scaly plaque on the lower leg has not responded to appropriate eczema treatment. What diagnosis should be actively excluded?

Choose one answer, then submit
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Sources and review status3 sources · checked 27 Aug 2026 · clinical review pending+
Sources

Sources and review status

National guidance is shown before implementation-dependent detail. Typical adult dose examples remain subject to patient factors, contraindications and the live BNF or specialist protocol. Source check completed 27 Aug 2026; clinical approval remains outstanding.

  • NHS Bowen diseaseMorphology, progression, treatment and follow-up.
  • NICE NG12 suspected cutaneous SCC referralUrgent invasive-SCC referral.
  • Efudix 5% cream SmPCTopical fluorouracil use and safety.

Editorial contact: Doctor’s Passport editorial team. Source-check date is separate from clinical approval. Report a content problem · Content changes

Authoring stateComplete draftClinical stateAwaiting reviewJurisdictionUnited Kingdom
3
Use pathology to plan margins, nodal assessment and follow-up rather than assuming the whole plaque remains in situ.
03Persistent or recurrent diseaseReconfirm before retreatingA plaque does not clear or returns after an appropriate course.+
  1. 1AlternativeVerify treatment field and adherence and examine for invasion, contact reaction and an alternative diagnosis.
  2. 2Biopsy the most suspicious residual area and retrieve prior pathology.
  3. 3EscalationEscalate to excision, margin-controlled surgery or another specialist modality based on site and updated histology.
Key medicines and prescribing safety1 treatment · regimens, roles and cautions+
A non-surgical topical option for selected Bowen disease where adequate follow-up is available.

Fluorouracil 5% cream

Apply a thin layer once or twice daily to the precisely mapped lesion for three to four weeks or according to specialist site-specific instructions.

Avoid pregnancy, eyes and mucosa; expected inflammation can be severe, and induration, infection, excessive ulceration or non-response requires review rather than automatic extension.