Conditions › Keratoacanthoma (KA)
Keratoacanthoma – Consultant Diagnosis of Rapidly Growing Skin Nodules in London
Keratoacanthoma (KA) is a rapidly growing skin tumour that resembles squamous cell carcinoma (SCC). Although it is generally considered benign, KA behaves aggressively and requires urgent evaluation and often surgical removal to rule out cancer. At Skinhorizon Clinic in London, we provide fast, expert dermatological assessment, accurate diagnosis, and safe treatment options.
Call Us Book ConsultationWhat is keratoacanthoma?
Keratoacanthoma (KA) is a skin lesion that closely resembles squamous cell carcinoma (SCC), a type of skin cancer. It typically presents as a fast-growing, dome-shaped nodule with a central keratin-filled crater. Although KA is generally classified as a low-grade skin tumour, it behaves aggressively and must be treated with the same urgency as SCC because they are clinically and histologically difficult to distinguish. For this reason, dermatologists often treat KA as if it were SCC until proven otherwise.
Causes and risk factors
The exact cause of keratoacanthoma remains unclear, but several factors contribute to its development:
- Ultraviolet (UV) radiation: Chronic sun exposure is the most significant risk factor.
- Fair skin type: Individuals with light skin, hair, and eyes are more vulnerable.
- Older age: Most cases occur in people over 50 years old.
- Male sex: Slightly more common in men.
- Immunosuppression: People with organ transplants, HIV, or long-term immunosuppressive therapy have higher risk.
- HPV infection: Human papillomavirus may play a role in some cases.
- Trauma or injury: KAs sometimes develop in sites of previous trauma or scarring (Koebner phenomenon).
Symptoms and clinical features
Keratoacanthoma typically appears on sun-exposed skin such as the face, forearms, and hands. Key features include:
- A rapidly growing, dome-shaped nodule, usually 1–2 cm in size.
- A central keratin plug giving the lesion a volcano-like appearance.
- Growth occurs over weeks to months, much faster than most skin cancers.
- Lesions may ulcerate, crust, or bleed.
- Occasionally, lesions regress spontaneously over months, but this is unpredictable.
Because KA so closely resembles SCC, a biopsy or excision is usually required for diagnosis. Dermatologists err on the side of caution and treat it as potentially malignant.
Diagnosis and investigations
The diagnosis of keratoacanthoma is mainly clinical, but confirmatory tests are needed:
- Dermatological examination: Careful inspection of size, shape, and growth pattern.
- Biopsy: Excisional biopsy is preferred to remove the lesion fully and confirm histology.
- Differential diagnosis: Must be distinguished from squamous cell carcinoma, basal cell carcinoma, actinic keratosis, and cutaneous horn.
Given the overlap with SCC, excision is both diagnostic and therapeutic.
Urgent Diagnosis for Keratoacanthoma in Central London
Book a consultation in Maida Vale for rapid assessment of new or fast-growing skin lumps. We provide expert diagnosis of keratoacanthoma and rule out skin cancer if needed.
Call Us Book ConsultationTreatment options
Surgical excision
Complete surgical removal is the gold standard. Standard excision or Mohs micrographic surgery may be used depending on location and recurrence risk. This ensures both diagnosis and cure.
Curettage and cautery
In some cases, curettage (scraping) and cautery may be appropriate, especially for smaller lesions.
Cryotherapy
Freezing with liquid nitrogen can be considered but is less reliable than excision.
Intralesional therapy
Injections of methotrexate or 5-fluorouracil into the lesion have been used in select cases, particularly where surgery is not possible.
Radiotherapy
Reserved for patients unfit for surgery or with multiple lesions.
Complications
Keratoacanthomas are generally benign but can cause problems if untreated:
- Local destruction: Deep invasion can damage surrounding tissues.
- Scarring: Surgical excision may leave scars, especially on the face.
- Disfigurement: Visible lesions can affect self-esteem and confidence.
- Progression to SCC: Some experts believe KA may represent a variant of SCC; rare cases progress to invasive cancer.
Prognosis
The outlook for keratoacanthoma is excellent if diagnosed early and treated appropriately. Most patients achieve complete cure with excision. Recurrence is uncommon but can occur, particularly in immunosuppressed individuals or in cases with multiple lesions. Monitoring for recurrence or other skin cancers is important given the shared risk factors.
Prevention
- Avoid excessive sun exposure.
- Use broad-spectrum sunscreen daily.
- Wear protective clothing and hats outdoors.
- Regular skin checks for those at higher risk.
- Prompt evaluation of any new or rapidly growing lesions.
Why choose Skinhorizon for keratoacanthoma management?
- Consultant dermatologist expertise in diagnosing and treating complex skin tumours.
- On-site minor surgery for rapid and safe lesion removal.
- Histopathology support to confirm accurate diagnosis.
- CQC-regulated clinical environment in central London.
- Personalised aftercare and scar management options.
Your first visit — what to expect
- History: Medical history, sun exposure, immune status, and details of the lesion.
- Examination: Careful inspection of lesion size, shape, and location.
- Biopsy or excision: Immediate removal may be recommended for diagnosis and treatment.
- Treatment planning: Discussion of surgical options and aftercare.
- Follow-up: Wound review, pathology results, and skin cancer prevention advice.
Reviewed by: Dr Mohammad Ghazavi, Consultant Dermatologist
Skinhorizon Clinic, 4 Clarendon Terrace, Maida Vale, London W9 1BZ
Last reviewed: 21 August 2025
Get rapid, expert treatment for keratoacanthoma to rule out cancer and restore skin health safely at Skinhorizon Clinic London.
Call Us Book ConsultationKeratoacanthoma FAQs
What does a keratoacanthoma look like and how quickly does it grow?
Keratoacanthoma is usually a dome-shaped, reddish nodule with a central keratin plug. It grows rapidly over a few weeks, often reaching 1–2 cm in size.
Is keratoacanthoma cancerous or benign?
Keratoacanthoma is considered a low-grade skin tumour. However, because it is almost indistinguishable from squamous cell carcinoma, it must be treated as potentially malignant until removed and analysed.
Can keratoacanthoma go away without treatment?
Some keratoacanthomas regress spontaneously over months, but this is unpredictable. Because they mimic SCC, treatment is always recommended to confirm diagnosis and prevent complications.
What is the best treatment for keratoacanthoma?
Complete surgical excision is the preferred treatment, ensuring both removal and accurate diagnosis. In some cases, Mohs surgery or alternative therapies may be advised.
Who is at greatest risk of developing keratoacanthoma?
People over 50 with fair skin, extensive sun exposure, or weakened immune systems are most at risk. Organ transplant patients and those with a history of skin cancer require extra vigilance.