Angiokeratomas

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:

Sporadic angiokeratoma
Angiokeratoma of Fordyce
Angiokeratoma circumscriptum
Fabry syndrome (angiokeratoma corporis diffusum)

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.

Distinguishing features

Angiokeratomas
Sporadic angiokeratoma	Scrotal angiokeratomas (Fordyce)	Vulvar angiokeratomas (Fordyce)
Angiokeratoma circumscriptum

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 & feet May result in corneal opacities, kidney failure, heart failure, strokes, arthritis, colitis & many other problems.

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

References:

OMIM – Online Mendelian Inheritance in Man (search term Angiokeratomas)
Autosomal recessive congenital ichthyosis – GeneTests GeneReviews

On DermNet NZ:

Vascular skin problems
Capillary vascular malformation
Genital skin problems
Fordyce spots – sebaceous hyperplasia of the lips

Other websites:

emedicine dermatology, the online textbook

Author: Vanessa Ngan, staff writer