Telangiectases appear on the skin and mucous membranes as small, dull red, linear, stellate or punctate markings. They represent dilatations (expansion, stretching) of pre‐existing vessels without any apparently new vessel growth occurring. They can be present anywhere on the skin and can lead to distress due to cosmetic issues arising from them. Some of them can be caused by serious underlying disease and need to be seen by a doctor to ascertain their etiology.
Telangiectasias can be primary or secondary.
- Generalized essential telangiectasia
- Hereditary benign telangiectasia
- Hereditary haemorrhagic telangiectasia
- Unilateral naevoid telangiectasia
- Bloom syndrome
- Vascular naevi (naevus flammeus)
- Prolonged vasodilatation (rosacea, venous disease, calcium‐channel blocking drugs, smoking, drinking alcohol)
- Chronic UV exposure (ageing skin) and post irradiation
- Atrophy (poikiloderma and steroid induced)
- Collagen vascular disease
- Raynaud phenomenon, CREST syndrome, scleroderma, morphoea lupus erythematosus
- Mastocytosis: telangiectasia macularis eruptiva perstans
- HIV infection
- Miscellaneous genodermatoses
- Spider naevi
KTP (532 nm) laser (frequency doubled Nd:YAG laser). By passing the emission from a Nd:YAG (1064 nm) laser through a KTP crystal the emission frequency can be doubled with a halving of the wavelength from 1064 nm to 532 nm. The emissions may be flashlamp or diode pumped and are characterized by trains of short pulses that summate to give a wide, pulse‐like or ‘quasi‐continuous’ effect with a low risk of producing purpura. Light produced by KTP lasers is highly absorbed by haemoglobin (and melanin) but its wavelength penetrates only superficially. They are widely used, with or without cooling devices, to treat small facial vessels.