DermNet NZ

Facts about the skin from DermNet New Zealand Trust. Topic index: A B C D E F G H I J K L M N O P Q R S T U V W X Y Z


What are angiokeratomas?

Angiokeratomas are small dark red to purple raised spots. They may also have a rough scaly surface. They are composed of surface blood vessels (dilated capillaries). Often unnoticed, they may become crusty and bleed if accidentally scratched or damaged, or a harmless clot may form in the lesion (thrombosis), changing the colour to dark purple or black overnight.

There are several types of angiokeratomas:

Angiokeratomas Angiokeratoma Angiokeratoma
Solitary angiokeratoma
Scrotal angiokeratomas
Vulvar angiokeratomas
Type of angiokeratoma Description
Sporadic angiokeratoma
  • Solitary lesions
  • Common in those over 40 years
Angiokeratoma of Fordyce
  • Most commonly found on the scrotum. Also found on the shaft of the penis, labia majora of the vulva, inner thigh and lower abdomen
  • Most prevalent in those over 40 years
  • Men are more often affected than women
  • May be a single lesion or multiple lesions (>100)
  • Lesions are small, red and less scaly in younger patients whilst in older patients they tend to be larger, blue/black and with overlying scales
  • Usually symptomless and may only be noticed when they bleed after scratching or intercourse
Angiokeratoma circumscriptum
  • Rare birthmark (vascular malformation). May be present at birth but can occur later in childhood or adulthood
  • Females are more affected than men 3:1
  • Cluster of lesions on a small area of the leg or trunk
  • Over time lesions may darken in colour and change shape and size
Fabry syndrome (angiokeratoma corporis diffusum)
  • Rare serious inherited disorder caused by a deficiency of an alpha-galactosidase enzyme, ceramide trihexosidase
  • Excessive quantities of glycosphingolipids are deposited in blood vessels and internal organs
  • More severe in males than females
  • Angiokeratomas are widespread, most numerous on lower trunk and groin area
  • May present with fever and painful hands and feet
  • May result in corneal opacities, kidney failure, heart failure, strokes, arthritis, colitis and many other problems.

What causes angiokeratomas and who gets them?

Apart from Fabry syndrome, which is caused by a genetic defect, the cause of other angiokeratomas is unknown.

What is the treatment for angiokeratomas?

Angiokeratomas are harmless surface vascular lesions that can usually be left alone. As the black spots sometimes resemble melanoma, a skin biopsy may be performed to rule out malignancy and allay any fears.

If bleeding becomes a concern or treatment is requested for cosmetic purposes, they can be removed. Surgical options include excision, laser therapy, cryotherapy or electrocautery.

Related information


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Author: Vanessa Ngan, staff writer

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