Retiform purpura is the result of total vascular blockage and damage to the

skin Skin is the layer of usually soft, flexible outer tissue covering the body of a vertebrate animal, with three main functions: protection, regulation, and sensation. Other animal coverings, such as the arthropod exoskeleton, have different ...

blood vessels Blood vessels are the tubular structures of a circulatory system that transport blood throughout many animals’ bodies. Blood vessels transport blood cells, nutrients, and oxygen to most of the tissues of a body. They also take waste an ...

. The skin then shows

lesions A lesion is any damage or abnormal change in the tissue of an organism, usually caused by injury or diseases. The term ''Lesion'' is derived from the Latin meaning "injury". Lesions may occur in both plants and animals. Types There is no de ...

, appearing due to

intravascular Blood vessels are the tubular structures of a circulatory system that transport blood throughout many animals’ bodies. Blood vessels transport blood cells, nutrients, and oxygen to most of the tissues of a body. They also take waste and c ...

issues where clots,

proteins Proteins are large biomolecules and macromolecules that comprise one or more long chains of amino acid residues. Proteins perform a vast array of functions within organisms, including catalysing metabolic reactions, DNA replication, re ...

, or

emboli An embolism is the lodging of an embolus, a blockage-causing piece of material, inside a blood vessel. The embolus may be a blood clot (thrombus), a fat globule (fat embolism), a bubble of air or other gas ( gas embolism), amniotic fluid (amnio ...

block skin vessels. They can also result from direct harm to the vessel walls, as seen in conditions like

vasculitis Vasculitis is a group of disorders that destroy blood vessels by inflammation. Both artery, arteries and veins are affected. Lymphangitis (inflammation of lymphatic vessels) is sometimes considered a type of vasculitis. Vasculitis is primarily c ...

calciphylaxis Calciphylaxis, also known as calcific uremic arteriolopathy (CUA) or “Grey Scale”, is a rare syndrome characterized by painful skin lesions. The pathogenesis of calciphylaxis is unclear but believed to involve calcification of the small bloo ...

, and certain severe opportunistic infections.

Pathophysiology

Retiform purpura is a

cutaneous Skin is the layer of usually soft, flexible outer tissue covering the body of a vertebrate animal, with three main functions: protection, regulation, and sensation. Other animal coverings, such as the arthropod exoskeleton, have different d ...

morphology Morphology, from the Greek and meaning "study of shape", may refer to: Disciplines *Morphology (archaeology), study of the shapes or forms of artifacts *Morphology (astronomy), study of the shape of astronomical objects such as nebulae, galaxies, ...

characterized by a branching ( reticular), non-blanching (purpuric) patch, plaque, or lesion that develops when blood vessels supplying the skin become obstructed. This blockage leads to downstream cutaneous

ischemia Ischemia or ischaemia is a restriction in blood supply to any tissue, muscle group, or organ of the body, causing a shortage of oxygen that is needed for cellular metabolism (to keep tissue alive). Ischemia is generally caused by problems ...

, or insufficient blood supply to the skin, causing

purpura Purpura () is a condition of red or purple discolored spots on the skin that do not blanch on applying pressure. The spots are caused by bleeding underneath the skin secondary to platelet disorders, vascular disorders, coagulation disorders, ...

necrosis Necrosis () is a form of cell injury which results in the premature death of cells in living tissue by autolysis. The term "necrosis" came about in the mid-19th century and is commonly attributed to German pathologist Rudolf Virchow, who i ...

, and potentially

ulceration An ulcer is a discontinuity or break in a bodily membrane that impedes normal function of the affected Organ (biology), organ. According to Robbins's pathology, "ulcer is the breach of the continuity of skin, epithelium or mucous membrane caus ...

. The obstruction in the

dermal The dermis or corium is a layer of skin between the epidermis (with which it makes up the cutis) and subcutaneous tissues, that primarily consists of dense irregular connective tissue and cushions the body from stress and strain. It is divided i ...

and subcutaneous

vasculature In vertebrates, the circulatory system is a system of organs that includes the heart, blood vessels, and blood which is circulated throughout the body. It includes the cardiovascular system, or vascular system, that consists of the heart an ...

results in

hemorrhage Bleeding, hemorrhage, haemorrhage or blood loss, is blood escaping from the circulatory system from damaged blood vessels. Bleeding can occur internally, or externally either through a natural opening such as the mouth, nose, ear, urethra, ...

secondary to skin

, which can further lead to skin

and

. This

can occur in a variety of disorders.

Signs and symptoms

Retiform purpura can present as non-raised large patches of

, with angulated or net-like border. They can present as painful dark red or purple patches or plaques with bordering branching and central purpura, necrosis, and/or

. They can vary in size from small (1–2 cm) to large (>10 cm), and may be single or multiple, localized or disseminated. The branching may only be seen at the edge of one or two lesions but is still the clue to this diagnosis and a potentially serious underlying condition. Inflammatory retiform purpura consists of redness around the lesion with associated central necrosis caused by vasculitic or infectious processes. Noninflammatory retiform purpura refers to lesions with central

with surrounding redness caused by the occlusive process. There can be significant overlap between these two classifications. Pain within lesions is common and may be severe.

Associated disorders

There are several vasculopathy disorders that can present with retiform purpura. Some thrombotic and coagulopathic disorders are

disseminated intravascular coagulation Disseminated intravascular coagulation (DIC) is a condition in which blood clots form throughout the body, blocking Microvessel, small blood vessels. Symptoms may include chest pain, shortness of breath, leg pain, problems speaking, or problems ...

(DIC), hypercoagulable states (like

antiphospholipid antibodies Antiphospholipid syndrome, or antiphospholipid antibody syndrome (APS or APLS), is an autoimmune, hypercoagulable state caused by antiphospholipid antibodies. APS can lead to blood clots (thrombosis) in both arteries and veins, pregnancy-relate ...

thrombotic thrombocytopenic purpura Thrombotic thrombocytopenic purpura (TTP) is a blood disorder that results in thrombi, blood clots forming in small blood vessels throughout the body. This results in a thrombocytopenia, low platelet count, hemolytic anemia, low red blood cells d ...

(TTP),

warfarin Warfarin, sold under the brand name Coumadin among others. It is used as an anticoagulant, anticoagulant medication. It is commonly used to prevent deep vein thrombosis and pulmonary embolism, and to protect against stroke in people who ha ...

-induced skin necrosis,

heparin-induced thrombocytopenia Heparin-induced thrombocytopenia (HIT) is the development of thrombocytopenia (a low platelet count), due to the administration of various forms of heparin, an anticoagulant. HIT predisposes to thrombosis (the abnormal formation of blood clots in ...

, and paroxysmal nocturnal

hemoglobinuria Hemoglobinuria is a condition in which the oxygen transport protein hemoglobin is found in abnormally high concentrations in the urine. The condition is caused by excessive intravascular hemolysis, in which large numbers of red blood cells (RBC ...

. Some intravascular protein deposition diseases causing retiform purpura are

cryoglobulinemia Cryoglobulinemia is a rare medical condition characterized by the presence of cryoglobulins in the blood. Cryoglobulins are abnormal proteins composed of immunoglobulins and sometimes complement components. Cryoglobulins specifically form g ...

(type I), cryofibrinogenemia, and

paraproteinemia Monoclonal gammopathy, also known as paraproteinemia, is the presence of excessive amounts of myeloma protein or monoclonal gamma globulin in the blood. It is usually due to an underlying immunoproliferative disorder or hematologic neoplasms, espe ...

. Some embolic disorders that may lead to retiform purpura include cholesterol emboli, septic emboli,

atrial myxoma A myxoma is a rare benign tumor of the heart. Myxomata are the most common primary cardiac tumor in adults, and are most commonly found within the left atrium near the valve of the fossa ovalis. Myxoma may also develop in the other heart chambers. ...

, or other manifestations like nonbacterial thrombotic

endocarditis Endocarditis is an inflammation of the inner layer of the heart, the endocardium. It usually involves the heart valves. Other structures that may be involved include the interventricular septum, the chordae tendineae, the mural endocardium, o ...

(marantic endocarditis, Libman-Sacks endocarditis) and

hypereosinophilic syndrome Hypereosinophilic syndrome is a disease characterized by a persistently elevated eosinophil count (≥ 1500 eosinophils/mm³) in the blood for at least six months without any recognizable cause, with involvement of either the heart, nervous sys ...

. Some vessel wall pathology resulting in retiform purpura could be

, septic vasculitis, vasculitis related to

autoimmune disease An autoimmune disease is a condition that results from an anomalous response of the adaptive immune system, wherein it mistakenly targets and attacks healthy, functioning parts of the body as if they were foreign organisms. It is estimated tha ...

or primary systemic vasculitis, or cryoglobulinemic vasculitis (cryoglobulinemia types 2 and 3). Other manifestation of retiform purpura can be seen in opportunistic infections,

primary hyperoxaluria Primary hyperoxaluria is a rare condition (autosomal recessive) resulting in increased excretion of oxalate (up to 600 mg a day from normal 50 mg a day), with oxalate stones being common. Signs and symptoms Primary hyperoxaluria is an a ...

, livedoid vasculopathy,

pyoderma gangrenosum Pyoderma gangrenosum is a rare, Inflammation, inflammatory skin disease where painful pustules or skin condition, nodules become ulcer (dermatology), ulcers that progressively grow. Pyoderma gangrenosum is not infectious. Treatments may include ...

, and vasculopathy or vasculitis due to

levamisole Levamisole, sold under the brand name Ergamisol among others, is a medication used to treat parasitic worm infections, specifically ascariasis and hookworm infections. It is taken by mouth. Side effects may include abdominal pain, vomiting, ...

-contaminated

cocaine Cocaine is a tropane alkaloid and central nervous system stimulant, derived primarily from the leaves of two South American coca plants, ''Erythroxylum coca'' and ''Erythroxylum novogranatense, E. novogranatense'', which are cultivated a ...

. The onset of widespread purpura, known as

purpura fulminans Purpura fulminans is an acute, often fatal, thrombotic disorder which manifests as blood spots, bruising and discolouration of the skin resulting from coagulation in small blood vessels within the skin and rapidly leads to skin necrosis and disse ...

, is a dangerous condition associated with disseminated intravascular coagulation (DIC). Determining the root cause of DIC is crucial for treatment. In severe opportunistic infections, retiform purpura can also emerge. It is vital to quickly assess patients showing signs of purpura fulminans, especially if they exhibit symptoms of

sepsis Sepsis is a potentially life-threatening condition that arises when the body's response to infection causes injury to its own tissues and organs. This initial stage of sepsis is followed by suppression of the immune system. Common signs and s ...

, serious sickness, or have weakened immune systems.

Patient assessment and management

A detailed history and physical examination are essential for patients with retiform purpura, as they can offer significant insights for diagnosis. Specifically, evaluating the skin's color and the spread of purpura is crucial.

Skin biopsies Skin biopsy is a biopsy technique in which a skin lesion is removed to be sent to a pathologist to render a microscopic diagnosis. It is usually done under local anesthetic in a physician's office, and results are often available in 4 to 10 day ...

of retiform purpura can be instrumental in diagnosing suspected retiform purpura, specifically a punch or an excisional wedge biopsy. If infection is suspected, a tissue culture with initial lab workup. Because the disease manifests in several ways, it is crucial to obtain the underlying

etiology Etiology (; alternatively spelled aetiology or ætiology) is the study of causation or origination. The word is derived from the Greek word ''()'', meaning "giving a reason for" (). More completely, etiology is the study of the causes, origins ...

when determining treatment plans.

References

{{Portal bar, Medicine Skin conditions resulting from physical factors Vascular-related cutaneous conditions