What is a dermatofibroma?
A dermatofibroma is a small growth of the deep connective tissue layers of the skin that produces a firm skin lump. They are brown in colour and may have a rim of pigmentation around them. Many individuals experience itching and pain in individual lesions. Multiple skin lesions are quite common and typical skin sites include the upper limbs, lower limbs and upper trunk. When examined, they feel like firm nodules and a dimple may form due to tethering of the lesion to deeper layers of the skin.
|pigmented dermatofibroma||dermatofibroma close-up||dermatofibroma skin-tethering|
What causes dermatofibroma?
The cause of dermatofibroma is not precisely known. Several factors are known to promote the growth of these skin lesions and these include insect bites and minor trauma. Hormonal influences may also be a factor as they are more commonly seen in younger women.
Is treatment necessary?
Dermatofibromas are not harmful and only need treatment if they are cause cosmetic embarrassment, excessive itching, or if they are painful. Rarely, the doctor may want to remove the skin lesion to exclude a skin cancer.
Freezing with liquid nitrogen may be used to relieve the itching and soreness produced by small dermatofibroma. This treatment is frequently used by doctors for many types of skin lesions. Light freezing usually causes no permanent damage to the skin, however, cryotherapy may cause loss in skin colour (hypopigmentation), darkening of the skin (hyperpigmentation), and rarely scarring. It is not very effective for larger lesions because they tend to involve the deeper layers of the skin.
Troublesome dermatofibroma need to be surgically removed with a local anaesthetic injection. The whole skin lesion needs to be cut out because dermatobroma originate from the deeper layers of the skin and the resulting wound is then closed with stitches. These are typically removed after 7-10 days. Skin surgery will produce a small scar. It is always important to realise that the scar may be more of a cosmetic problem than the original skin lesion. Skin surgery tends to produce less optimal results on the lower leg compared to other skin sites.