Sudden onset of multiple SKs → controversial paraneoplastic association (internal malignancy).
Unusual rapid increase warrants careful assessment but is usually benign.

Differential Diagnosis

Actinic keratosis: Rough, scaly papules on sun-damaged skin (pre-SCC).
Melanoma: Check ABCDE criteria (Asymmetry, Border irregularity, Colour variation, Diameter >6 mm, Evolving).
Pigmented BCC: Pearly edge, telangiectasia, rolled border.
Naevi (moles): Smaller, uniform colour, less "stuck-on."
Warts: Often on hands/feet, may have black punctate dots.
Dermatosis papulosa nigra: Small, smooth facial papules in darker skin tones.

Clinical Pearl: If in doubt, use dermoscopy or biopsy/excision to exclude malignancy.

Diagnosis

Clinical Diagnosis

Classic "stuck-on" morphology is usually diagnostic.

Dermoscopy

Milia-like cysts, comedo-like openings, "crypt-like" appearance.
Essential if lesion is atypical.

Histopathology (if biopsied)

Benign epidermal proliferation with keratin-filled "horn cysts."

Management

Reassurance

Benign condition, no treatment required unless symptomatic.

Indications for Removal

Irritation, itching, bleeding, or crusting (trauma).
Cosmetic concern.
Diagnostic uncertainty.

Removal Methods

Cryotherapy (liquid nitrogen): Quick, may cause hypopigmentation.
Curettage/shave excision: If cryotherapy unsuitable or biopsy needed.
Electrosurgery: Requires local anaesthetic.
Laser ablation: Used in dermatology clinics.

Follow-Up

Not required unless lesion changes (size, colour, shape) or new atypical lesions develop.

Red Flags

Rapid growth, colour change, ulceration, or bleeding → suspicious for malignancy.
Atypical features → consider biopsy/excision.

Seborrhoeic keratosis

Clinical Features

Appearance
- Well-defined, round or oval, “stuck-on” plaque.
- Colour can vary: light brown, dark brown, black, or even skin-coloured.
- Surface is usually rough, warty, or crumbly. Occasionally can appear smooth or waxy.
Distribution
- Commonly appear on the trunk, face, neck, scalp, and limbs.
- They spare mucosal surfaces (e.g., inside the mouth) and usually do not appear on palms/soles.
Symptomatology
- Usually asymptomatic.
- Can become irritated, inflamed, or pruritic if rubbed by clothing or accidentally traumatised.
Sign of Leser-Trélat
- Sudden eruption of multiple SKs, sometimes associated with pruritus, has been described as a paraneoplastic phenomenon (classically with internal malignancy), but remains controversial. Realistically, most new or multiple SKs are benign.
- Clinically, any unusual, sudden, or explosive increase in number or change in morphology of SKs warrants careful consideration of underlying causes or malignancy elsewhere, but the association is not strongly established.

Differential Diagnosis

Solar (actinic) keratoses: These present as rough, scaly papules on sun-damaged skin (e.g., forearms, face, scalp). Solar keratoses can potentially progress to squamous cell carcinoma (SCC).
Pigmented lesions:
- Melanoma: Look out for ABCDE features (Asymmetry, Border irregularity, Colour variation, Diameter > 6 mm, Evolving lesions).
- Pigmented basal cell carcinoma (BCC): Usually has a pearly edge, telangiectasia, or a rolled border.
- Naevi (moles): Usually uniform in colour, smaller, and less “stuck-on” than SKs.
Warts (verrucae): Typically found on hands or feet, caused by HPV; may appear less pigmented, can have punctate black dots on paring.
Dermatosis papulosa nigra: A variant of SK seen particularly in individuals with darker skin tones, presenting as small, smooth papules on the face.

Clinical Pearl: The distinction between SKs and other pigmented skin lesions such as melanoma can be challenging. When in doubt, seek dermoscopic evaluation or refer for biopsy/excision to exclude malignancy.

Diagnosis

Clinical Diagnosis
- Often straightforward due to characteristic “stuck-on” morphology.
- Lesions can vary in colour and form but typically remain well-defined with a verrucous (wart-like) surface.
Dermoscopy
- Common features: milia-like cysts, comedo-like openings, and a “crypt-like” appearance.
- Dermoscopic evaluation is essential if the lesion is atypical or if there is any concern for malignancy.
Histopathology (if biopsied/excised)
- Shows proliferation of benign epidermal cells with keratin-filled “pseudocysts” (horn cysts).
- Confirms benign diagnosis.

Management

Reassurance
- Seborrhoeic keratoses are benign and do not require treatment unless symptomatic, traumatised, or for cosmetic reasons.
- Patients often benefit from education and reassurance about their harmless nature.
Indications for Removal
- Irritation or itching (e.g., rubbing against clothing).
- Bleeding or crusting due to repeated trauma.
- Cosmetic concerns if the patient finds them unsightly.
- Diagnostic uncertainty—if there is any suspicion about the nature of the lesion.
Removal Methods
- Cryotherapy (liquid nitrogen): Quick, easily performed in general practice. May leave a lighter patch of skin (hypopigmentation).
- Curettage and/or shave excision: May be utilised if cryotherapy is not suitable or to send tissue for histopathological analysis.
- Electrosurgery: Useful for raised lesions. Local anaesthetic required.
- Laser ablation: Generally used by dermatologists or in specialised clinics.
- Topical therapies: Not typically first-line for classic SKs.
Follow-Up
- Routine follow-up is generally not necessary unless lesions are suspicious or the patient desires further removals.
- Advise patients to return if they notice any change in size, colour, or shape of existing lesions or development of new atypical lesions (to exclude melanoma or other skin cancers).

Red Flags

Rapidly changing lesion: Rapid growth, colour change, bleeding, or ulceration raises suspicion of malignancy (e.g., melanoma, SCC).
Atypical presentation: If a lesion does not have typical clinical/dermoscopic features of SK, further evaluation (biopsy/excision) is prudent.

Bookmark Failed!

Bookmark Saved!

Refresh