They must be differentiated from other causes of persistent reticulated vascular lesions, such as those in the following table:

Histology
Some patients have a few or no histopathologic abnormalities. Histological examination of a biopsy may show an increase in the number and size of capillaries and veins (rarely lymphatics), dilated capillaries located in the deeper dermis, and hyperplasia and swollen endothelial cells with occasional dilated veins and venous lakes. Associated abnormalities
Associated abnormalities include the following:

Body asymmetry (extremities; macrocephaly)
Glaucoma
Cutaneous atrophy
Neurological anomalies
Vascular anomalies (nevus flammeus /Sturge-Weber/Klippel-Trénauna Adams Oliver syndrome)
Psychomotor and/or mental retardation
Chronic ulceration that can complicate long-term CMTC
Chronic urticaria. Treatment
In general, there is no treatment available for CMTC, although associated abnormalities can be treated. In the case of limb asymmetry, when no functional problems are noted, treatment is not warranted, except for an elevation device for the shorter leg. Laser therapy has not been successful in the treatment of CMTC, possibly due to the presence of many large and deep capillaries and dilated veins. Pulsed-dye laser and long-pulsed-dye laser have not yet been evaluated in CMTC, but neither argon laser therapy nor YAG laser therapy has been helpful.When ulcers develop secondary to the congenital disease, antibiotic treatment such as oxacillin and gentamicin administered for 10 days has been prescribed. In one study, the wound grew Escherichia coli while blood cultures were negative. Prognosis
The prognosis is favorable in most patients with an isolated cutaneous abnormality. In the majority of cases, both the vivid red marking and the difference in circumference of the extremities regress spontaneously during the first year of life.
Sarcoidosis, an inflammatory disease,  involves the skin in about 25% of patients. The most common lesions are erythema nodosum, plaques, maculopapular eruptions, subcutaneous nodules, and lupus pernio. Treatment is not required, since the lesions usually resolve spontaneously in two to four weeks. Although it may be disfiguring, cutaneous sarcoidosis rarely causes major problems. Classification
Morphology
Ulcerative sarcoidosis is a cutaneous condition affecting roughly 5% of people with sarcoidosis. : 710 Annular sarcoidosis is a cutaneous condition characterized by papular skin lesions arranged in annular
patterns, usually with a red-brown hue. : 709

Pattern
Morpheaform sarcoidosis is a very rare cutaneous condition characterized by specific cutaneous skin lesions of sarcoidosis accompanied by substantial fibrosis, simulating morphea. : 711 Erythrodermic sarcoidosis is a cutaneous condition and very rare form of sarcoidosis. : 710 Hypopigmented sarcoidosis is a cutaneous condition characterized by areas of hypopigmented skin. It is usually diagnosed in darkly pigmented races and may be the earliest sign of sarcoidosis. : 709 Papular sarcoid is a cutaneous condition characterized by papules, which are the most common morphology of cutaneous sarcoidosis. : 708 Ichthyosiform sarcoidosis is a cutaneous condition resembling ichthyosis vulgaris or acquired ichthyosis, with fine scaling usually on the distal extremities, by caused by sarcoidosis. : 710

Location
Subcutaneous sarcoidosis (also known as "Darier–Roussy disease" and "Darier-Roussy sarcoid") is a cutaneous condition characterized by numerous 0.5- to 0.3-cm deep-seated nodules on the trunk and extremities. : 710 Scar sarcoid (also known as "Sarcoidosis in scars") is a cutaneous condition characterized by infiltration and elevation of tattoos and old flat scars due to sarcoidosis.