This document provides an overview of common birthmarks and naevi (moles). It discusses the main types including melanocytic naevi (moles), vascular birthmarks like infantile haemangiomas and vascular malformations, Mongolian spots, and sebaceous naevi. While most birthmarks are harmless and need no treatment, some like large congenital melanocytic naevi, ulcerating haemangiomas, or vascular malformations associated with other conditions may require management with treatments like laser therapy or medications.
2. Objectives
To understand that there are many different types of
birthmarks and naevi.
To appreciate the main clinical characteristics of the most
common types.
3. Paediatric dermatology
Many skin conditions affect children.
Atopic dermatitis and viral exanthems have been
discussed. Most inflammatory dermatoses can affect
both adults and children.
Here we will only discuss the more common naevi and
birthmarks.
4. Naevi and birthmarks
A naevus is literally a “maternal impression.”
They can be interpreted as aberrations of embryological
development comprising a proliferation of one or more
cell types.
Any of the cell types in the skin can produce a naevus.
5. The most common naevi are
melanocytic naevi
vascular naevi
and sebaceous naevi
6. Melanocytic naevi
These are usually brown, often hairy lesions of variable size.
They usually need no specific management.
They can be excised for cosmetic reasons.
Acquired melanocytic naevi are related to sun
exposure and increase in number in the late teens
and early twenties. These are the common "moles"
all fair skinned people living in Australia develop.
Congenital melanocytic naevi are present at birth.
They are categorized according to size
Small up to 1.5cm maximum diameter
Medium 1.5cm to 20cm maximum diameter
Giant greater than 20cm maximum diameter
10. There are other pigmented birthmarks.
The most common is the Mongolian Spot. These are very
common in pigmented races. They represent dermal
melanocytosis, have no medical implications and fade by
5-7 years.
12. Vascular birthmarks
There are two main types – infantile haemangiomas and
vascular malformations.
It is very important to understand the difference in these as
the natural histories and managements are completely
different.
13. Infantile haemangiomas
These are benign tumours of vascular endothelium,
characterized by a proliferative and an involutional
phase.
Most often they can be observed with no specific
management as they involute.
Infantile haemangiomas can be superficial (“strawberry
birthmark,”) mixed or deep (“cavernous.”)
17. Generally haemangiomas proliferate over 6-10 months and
involute over 5-7 years.
However, complications of haemangiomas include
Ulceration
Ocular compromise
Airway compromise
High output cardiac failure
Disseminated intravascular coagulation
Systemic involvement
Scarring
Such occurences may necessitate treatment with vascular
laser, topical steroids, systemic steroids or systemic
propranolol
19. Vascular malformations
These are a developmental anomaly, predominantly
capillary in origin, but sometimes derived from venous,
arterial or lymphatic vessels. They are present at birth
and persist throughout life.
Vascular laser is often used to treat these early as they
generally get thicker and more prominent over time.
They are commonly known as “port wine stains.”
21. Capillary vascular malformations can be associated with
other abnormalities.
The most well known syndrome is
Sturge-Weber Syndrome. This is a facial vascular
malformation involving at least a portion of V1 in
association with leptomeningeal angiomatosis and often
glaucoma.
23. Sebaceous naevi
These are birthmarks of sebaceous glands.
They are slightly raised, linear or oval in shape and
yellow or orange in colour.
They are most common on the scalp and often
devoid of hair.
They have a 15% chance of developing a
malignancy so are frequently excised.
Rarely, and if very large they can be associated
with abnormalities of bony growth, the eyes
and the central nervous system.
25. Conclusion
There are many different types of birthmarks and naevi.
This is a very brief introduction to the most common.
These lesions are usually harmless, but occasionally
there can be serious complications which require specific
management.
