April 2015 Dermatology Clinic
A pregnant woman, aged 29 years, presented with a unilateral rash. She recalled the rash being present since late childhood, but she said it has become more apparent since becoming pregnant. She denied any associated pruritus or pain. Her past medical history was negative for liver disease. Her only medications were prenatal vitamins. No family members had similar lesions. Her social history was negative for intravenous drug use or travel to areas endemic for hepatitis B or C. Physical examination was notable for a gravid woman with telangiectatic macules on the right side of her chest, extending down to the right arm.
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Telangiectasias are abnormal, small, persistently dilated blood vessels visible in skin as a result of vascular dilation.1 Unilateral nevoid telangiectasia (UNT) is a relatively rare cause of cutaneous telangiectasias.1
UNT, which may be congenital or acquired, is more frequently seen in women; rare cases are reported in men.2 In the acquired form, UNT usually develops in adulthood. Although usually sporadic, a rare familial form has been described with autosomal dominant inheritance.2
UNT is thought to be relatively rare, with 100 cases reported as of 1997.3 However, the true frequency is unknown and may be vastly underestimated due to underreporting as it is a benign and relatively well-known entity.
Skin disorders which present in a segmental form, such as UNT, are often a result of somatic mosaicism.3 It is hypothesized that an increase in estrogen receptors on blood vessels in affected areas and/or an increase in estrogen levels may result in UNT.1 Estrogens are thought to promote the formation of telangiectasias by promoting endothelium-dependent relaxation, increasing levels of nitric oxide and prostacyclins, and inhibiting vascular smooth muscle contraction. Since estrogen plays a key role in pathogenesis, it is not surprising that women are more commonly affected than men. Acquired forms of UNT are associated with conditions resulting in estrogen excess, such as pregnancy, puberty, and liver disease (e.g., cirrhosis and infection with hepatitis C virus).1 Oral contraceptives have also been associated with UNT.2 Most recently, it has been proposed that vascular endothelial growth factor may play a role in pathogenesis for UNT that develops in patients with underlying hepatic disease.4
UNT is characterized by fine, thread-like telangiectasias. As the name implies, UNT is usually unilateral, most commonly found in the trigeminal or upper cervical dermatomes.1 Although UNT most commonly affects the face, neck, upper extremities, and thorax, the lower extremities may also be affected.4 The telangiectasias may follow lines of Blaschkoid.1 Rare cases of bilateral UNT, in which the third and fourth cervical dermatomes are involved, have been described.2 Although the majority of lesions will be found in one dermatome, scattered telangiectasias may be seen at distant sites. These lesions are usually asymptomatic. There have been case reports of UNT developing in association with other skin disorders such as pyogenic granuloma and polymorphous light eruption.5 There are also case reports of associations with hyperthyroidism and chemotherapy, but, as these are isolated case reports, it is very likely that these are coincidental associations.5
Differential diagnosis varies depending on age of presentation. In infants, the differential might include infantile hemangioma. Precursors to hemangioma may often present as telangiectasias, but within two to six months of life, infantile hemangiomas rapidly proliferate, revealing the more characteristic appearance of infantile hemangiomas, which is a red vascular papule or plaque, a deep, soft subcutaneous nodule, or a combination of the two. In adults or children, the differential might include angioma serpiginosum, erythema ab igne, generalized essential telangiectasia, or telangiectasia macularis eruptiva perstans (TMEP).
Angioma serpiginosum is a rare vascular disorder that presents as a vascular cutaneous eruption.1 It is usually sporadic and typically develops in women in the first two decades of life.1 Affected areas are notable for deep red to purple pinpoint macules often arranged in a serpiginous pattern on the extremities. UNT is comprised of telangiectasias with a more thread-like appearance, whereas angioma serpiginosum is notable for pinpoint macules.1
Erythema ab igne has a characteristic cutaneous pattern that develops after chronic exposure to low levels of infrared heat. Historically, exposure to pot-bellied stoves was involved in the pathogenesis of erythema ab igne. More recently, heating pads and laptops have been reported to cause the condition. Erythema ab igne is characterized by macular erythema organized in a reticulated pattern. Telangiectasias are not the major feature of erythema ab igne, as it is in UNT.
Generalized essential telangiectasia is a primary disorder of telangiectasias that usually affects adult women. Sheets of telangiectasias develop, usually starting on the lower legs. This is generally followed by proximal progression, which results in a generalized distribution.1 Although the primary lesions are telangiectasias in both UNT and generalized essential telangiectasias, the major distinguishing factor is the distribution.1
TMEP is a relatively rare manifestation of mastocytosis that is also characterized by telangiectasias. Most forms of cutaneous mastocytosis have a positive Darier’s sign, which is characterized by an urticarial wheal that develops after scratching or vigorously rubbing a characteristic lesion.1 Darier’s sign is absent in UNT. However, in TMEP, there may be a low concentration of mast cells, when compared with other forms of cutaneous mastocytosis. For this reason, Darier’s sign is only variably elicited in TMEP. Therefore, TMEP is most reliably distinguished by its more generalized distribution from UNT.
The diagnosis of UNT is often made clinically, as distribution of the telangiectasias is key. Skin biopsy can confirm telangiectasias, notably dilated capillaries in the superficial dermis. However, once the diagnosis of telangiectasias is confirmed, the clinician must evaluate if the distribution is consistent with UNT.2 No laboratory tests are needed, but, if there are risk factors for either pregnancy or liver dysfunction, screening with a serum pregnancy test, liver function tests, and a hepatitis profile may be reasonable.2
Treatment of UNT is unnecessary as the condition is benign. Acquired cases may improve after addressing the underlying cause of estrogen excess. However, pulsed dye laser may be effective for patients concerned about the cosmetic appearance of the lesions.2 Camouflage cosmetic products may also improve appearance.
The patient in this case was not cosmetically bothered by these lesions, and we expected that the appearance would improve after delivery. However, she was lost to follow-up.
Audrey Chan, MD, is a pediatric dermatology fellow at Texas Children’s Hospital in Houston.
- Kelly R, Baker C. Other vascular disorders. In: Bolognia JL, Jorizzo JL, Schaffer JV, eds. Dermatology. 3rd ed. Philadelphia, Pa.: Elsevier Saunders; 2012: Chap. 106.
- James WD, Berger TG, Elston DM. Andrews’ Diseases of the Skin: Clinical Dermatology. 11th ed. Philadelphia, Pa.: Saunders Elsevier; 2011:579-580.
- Hynes LR, Shenefelt PD. Unilateral nevoid telangiectasia: occurrence in two patients with hepatitis C. J Am Acad Dermatol. 1997;36(5 Pt 2):819-822.
- Smith JA, Kamangar F, Prakash N, et al. Unilateral nevoid telangiectasia syndrome (UNTS) associated with chronic hepatitis C virus and positive immunoreactivity for VEGF. Dermatol Online J. 2014;20(6). Available at escholarship.org/uc/item/8g9268sf
- Tanglertsampan C, Chanthothai J, Phichawong T. Unilateral nevoid telangiectasia: case report and proposal for new classification system. Int J Dermatol. 2013;52(5):608-610.
All electronic documents accessed on March 30, 2015.