The most common presentation of Milroy Disease is bilateral lower extremity lymphedema, and may also be accompanied by hydrocele.

Primary lymphedema is a form of lymphedema which is not directly attributable to another medical condition.

It can be divided into three forms, depending upon age of onset: congenital lymphedema, lymphedema praecox, and lymphedema tarda.

Congenital lymphedema presents at birth. Lymphedema praecox presents from ages 1 to 35. This type of lymphedema accounts for 77–94% of all cases of primary lymphedema. Lymphedema tarda presents after age 35. This type of lymphedema usually develops as a result of a developmental abnormality being precipitated by some insult such as trauma, illness, or physical immobility. Compared to secondary lymphedema, primary lymphedema is more likely to involve the face, conjunctiva, and genitalia in association with any limbs involved.

It can be familial.

Milroy's disease (MD) is a familial disease characterized by lymphedema, commonly in the legs, caused by congenital abnormalities in the lymphatic system. Disruption of the normal drainage of lymph leads to fluid accumulation and hypertrophy of soft tissues. It is also known as Milroy disease, Nonne-Milroy-Meige syndrome and hereditary lymphedema.

It was named by Sir William Osler for William Milroy, a Canadian physician, who described a case in 1892, though it was first described by Rudolf Virchow in 1863.

The clinical manifestation and presentation of symptoms of lymphedema develop following a significant degree of injury. Secondary lymphedema is the lymphadenectomy and lymphatic injury following surgery, radiation, chemotherapy, and/or trauma which healing or regeneration of damaged lymphatics may occur with variable success.

Symptoms will include swelling, edema, and pain from a multitude of secondary complications (pressure, musculoskeletal disorder from asymmetry, restricted blood flow). Most patients will avoid discussing pain for many reasons, so this will require logical thinking or communication skills to assess. In advanced lymphedema, there may be the presence of skin changes such as discoloration, verrucous (wart-like) hyperplasia, hyperkeratosis, papillomatosis, and Ulcer (dermatology).

Lymphedema should not be confused with edema arising from venous insufficiency, which is not lymphedema. In addition to a compressive local environment of lymphedematous extremity, long standing venous compression potentially contributed to an increased propensity for thrombosis due to vascular changes from longstanding venous hypertension from a proximal compression or simply from a change in blood flow. However, untreated venous insufficiency can progress into a combined venous/lymphatic disorder. Proper imaging can help identify where the dysfunction is in the system, and is essential in identifying the source before treatment is decided.

Presented here is an extreme case of severe unilateral hereditary lymphedema which had been present for 25 years without treatment:

Lymphedema affects approximately 140 million people worldwide.

Lymphedema may be inherited (primary) or caused by injury to the lymphatic vessels (secondary). It is most frequently seen after lymph node dissection, surgery and/or radiation therapy, in which damage to the lymphatic system is caused during the treatment of cancer, most notably breast cancer. In many patients with cancer, this condition does not develop until months or even years after therapy has concluded. Lymphedema may also be associated with accidents or certain diseases or problems that may inhibit the lymphatic system from functioning properly. In tropical areas of the world, a common cause of secondary lymphedema is filariasis, a parasitic infection. It can also be caused by a compromising of the lymphatic system resulting from cellulitis.

While the exact cause of primary lymphedema is still unknown, it generally occurs due to poorly developed or missing lymph nodes and/or channels in the body. Lymphedema may be present at birth, develop at the onset of puberty (praecox), or not become apparent for many years into adulthood (tarda). In men, lower-limb primary lymphedema is most common, occurring in one or both legs. Some cases of lymphedema may be associated with other vascular abnormalities.

Secondary lymphedema affects both men and women. In women, it is most prevalent in the upper limbs after breast cancer surgery, in particular after axillary lymph node dissection, occurring in the arm on the side of the body in which the surgery is performed. Breast and trunk lymphedema can also occur but, go unrecognised as there is swelling in the area after surgery and its symptoms ( peau d' orange and/or an inverted nipple ) can be confused with post surgery fat necrosis. In Western countries, secondary lymphedema is most commonly due to cancer treatment. Between 38 and 89% of breast cancer patients suffer from lymphedema due to axillary lymph node dissection and/or radiation. Unilateral lymphedema occurs in up to 41% of patients after gynecologic cancer. For men, a 5-66% incidence of lymphedema has been reported in patients treated with incidence depending on whether staging or radical removal of lymph glands was done in addition to radiotherapy.

Head and neck lymphedema can be caused by surgery or radiation therapy for tongue or throat cancer. It may also occur in the lower limbs or groin after surgery for colon, ovarian or uterine cancer, in which removal of lymph nodes or radiation therapy is required. Surgery or treatment for prostate, colon and testicular cancers may result in secondary lymphedema, particularly when lymph nodes have been removed or damaged.

The onset of secondary lymphedema in patients who have had cancer surgery has also been linked to aircraft flight (likely due to decreased cabin pressure or relative immobility). For cancer survivors, therefore, wearing a prescribed and properly fitted compression garment may help decrease swelling during air travel.

Some cases of lower-limb lymphedema have been associated with the use of tamoxifen, due to the blood clots and deep vein thrombosis (DVT) that can be caused by this medication. Resolution of the blood clots or DVT is needed before lymphedema treatment can be initiated.

Meige lymphedema, also known as Meige disease, Late-onset lymphedema, and Lymphedema hereditary type 2, is an inherited disease in which patients develop lymphedema. The onset is between the ages of 1 and 35. Other causes of primary lympoedema include Milroy's disease which occurs before the age of 1, and lymphoedema tarda which occurs after the age of 35.

Meige disease,(Hereditary lymphedema type II), has its onset around the time of puberty. It is an autosomal dominant disease. It has been linked to a mutations in the ‘forkhead’ family transcription factor (FOXC2) gene located on the long arm of chromosome 16 (16q24.3). It is the most common form of primary lymphedema, and about 2000 cases have been identified. Meige disease usually causes lymphedema of the legs, however, other areas of the body may be affected, including the arms, face and larynx. Yellow toe nails occur in some individuals.

Lymphedema praecox is a condition characterized by swelling of the soft tissues in which an excessive amount of lymph has accumulated, and generally develops in females between the ages of nine and twenty-five.This is the most common form of primary lymphedema, accounting for about 80% of the patients.

The disease usually affects the lower legs or scrotum. The swelling is accompanied by rough nodules or wart-like plaques on the skin. If the disease is not treated, it eventually results in pain and immobility.

Stasis papillomatosis is a disease characterized by chronic congestion of the extremities, with blood circulation interrupted in a specific area of the body. A consequence of this congestion and inflammation is long-term lymphatic obstruction. It is also typically characterized by the appearance of numerous papules. Injuries can range from small to large plates composed of brown or pink, smooth or hyperkeratotic papules. The most typical areas where injuries occur are the back of the feet, the toes, the legs, and the area around a venous ulcer formed in the extremities, although the latter is the rarest of all. These injuries include pachydermia (thickening of the skin), lymphedema, lymphomastic verrucusis and elephantosis verracosa. The disease can be either localized or generalized; the localized form makes up 78% of cases. Treatment includes surgical and pharmaceutical intervention; indications for partial removal include advanced fibrotic lymphedema and elephantiasis. Despite the existence of these treatments, chronic venous edema, which is a derivation of stasis papillomatosis, is only partially reversible. The skin is also affected and its partial removal may mean that the skin and the subcutaneous tissue are excised. A side effect of the procedure is the destruction of existing cutaneous lymphatic vessels. It also risks papillomatosis, skin necrosis and edema exacerbation.

All etiologies lead to local dermal lymphostasis pathogenesis. A maximum variation was observed after the resection of block subcutaneous tissue in patients suffering from congenital lymphedema. Signals that the current condition are different, either in the dermis or in the subcutaneous area. In dermis, principal signs found are precollectors initial nodes, injection tank, the reticular distribution, cutaneous reflexes, and lymphatic cysts. On other hand in the subcutaneous area principal signs are; collectors, thinning, ectatic, tortuous, rest offs, reflux dermal, sclerosis, calcifications.

Although elephantiasis nostras resembles the elephantiasis caused by helminths, it is not a filarial disease. Instead, it is a complication of chronic lymphedema. Both elephantiasis nostras and filarial elephantiasis are characterized by impaired lymphatic drainage, which results in excess fluid accumulation.

People tend to gain weight in lipedematous areas and lose it in non-lipedematous areas, though there are cases where weight loss has resulted in improvement of the condition. Obese lipedema patients who undergo bariatric surgery lose fat primarily from the waist up. While lipedema presents itself in various ways, diagnosis is possible as early as pre-puberty when inner thigh pads present and at any age when fat gathers and drapes at knees.

Symptoms of lipedema include disproportionately large, column-like legs, legs unusually large to the knees, disproportionate hips, stomach or buttocks. As lipedema progresses, patients become increasingly heavy in the lower body. The additional, expanding fat cells interfere with the pathways of lymphatic vessels, and patients can develop secondary lymphedema, a condition known as lipo-lymphedema. Many lipedema patients cannot tolerate the compression garments associated with conventional lymphedema treatment because the underlying lipedematous fat is very painful, and those patients therefore are at risk for the side effects of uncontrolled lymphedema, including recurring blood infections and fibrosis. If not kept in check through a healthy lifestyle, lipo-lymphedema can worsen, and patients will become progressively less mobile.

The nails are markedly thickened with yellow to yellow-green discoloration of the nails. They grow slowly, at a rate of 0.25 mm/week or less. The nails may have ridges and increased side-to-side curvature, reduction of the white crescent and detachment of the nail from the nailbed. The nail changes may change over time.

Most people with yellow nail syndrome (four fifths) have lymphedema; it is symmetrical and typically affects both legs. It is the first symptom of the condition in about a third. Involvement of the arms and face is more unusual, as is lymphedema of the abdomen with ascites (fluid collection in the abdominal cavity) and fluid collection around the heart.

Various lung problems can occur in people with yellow nail syndrome. Many experience cough and shortness of breath. Forty percent of cases develop pleural effusions, which are collections of fluid in the pleural cavity (the space that contains the lungs and normally only has a minimal amount of fluid in it). About half of all people with yellow nail syndrome have either recurrent chest infections or a chronic lung condition known as bronchiectasis which causes chronic production of sputum with episodes of worsening. Forty percent of people with yellow nail syndrome have chronic sinusitis.

Yellow nail syndrome has been associated with some drugs, "e.g." penicillamine, bucillamine and gold sodium thiomalate.

Lymphedema is usually asymmetrical and can be either acquired (through surgery, trauma or infection damaging the lymphatic system) or congenital (hereditary changes in the lymphatic system). However, symmetrical enlargement of both lower limbs, from waist to ankles (i.e. gynoid fat) is a hallmark of lipedema. As the swelling continues and spreads from lower extremities to other parts of the body, the swelling is likely caused by slower lymphatic flow and changes in the lymphatic vessel structure caused by pressure in the lipedematous limbs. This is known as lipo-lymphedema. Lipo-lymphedema may also develop in combination with chronic venous insufficiency and other vascular disorders.

Lipedema can be underdiagnosed due the difficulty in differentiating it from other edemas and obesity. Trayes 2013 published some tools including tables and a flow chart that can be used to diagnose lipedema and other edemas.

Lipedema / Dercum’s Disease Differentiation

These conditions may co-exist. Dercum’s Disease is characterized by painful lipomas around the body.

Chronic inflammation can cause long term lymphatic obstruction. Typically, patients have disorders that present local nodes, primary lymphedema and chronic venous insufficiency. Erysipelas and trauma are major risk factors. Lymphatic edema can be developed in many acral cases accompanied by a thickening of the folds of the skin, hyperkeratosis and papillomatosis. Chronic venous edema is only partially reversible and soon becomes hard, especially confirming tenderness. All structures of the skin are affected. Dilated dermal lymphatic vessels with consequent superior organization and fibrosis result in papillomatosis. As dermal lymphatic stasis progreses, these skin changes become more marked and known as elephantiasis. Occasionally, tissue fibrosis and thickening may become so marked in the later stages of lymphedema that pitting is absent. Recurrent cellulitis, erysipelas and dermato-LAM-adenitis are complications of chronic lymphedema.

Postinflammatory lymphedema is a condition characterized by swelling of the soft tissues in which an excessive amount of lymph has accumulated, and is caused by repeated bacterial infections.

Signs and symptoms of CVI in the leg include the following:

- Varicose veins

- Itching (pruritus)

- Hyperpigmentation

- Phlebetic lymphedema

- Chronic swelling of the legs and ankles

- Venous ulceration

CVI in the leg may cause the following:

- Venous stasis

- Ulcers.

- Stasis dermatitis, also known as varicose eczema

- Contact dermatitis. Patients with venous insufficiency have a disrupted epidermal barrier, making them more susceptible than the general population to contact sensitization and subsequent dermatitis.

- Atrophie blanche. This is an end point of a variety of conditions, appears as atrophic plaques of ivory white skin with telangiectasias. It represents late sequelae of lipodermatosclerosis where the skin has lost its nutrient blood flow.

- Lipodermatosclerosis. This is an indurated plaque in the medial malleolus.

- Malignancy. Malignant degeneration is a rare but important complication of venous disease since tumors which develop in the setting of an ulcer tend to be more aggressive.

- Pain. Pain is a feature of venous disease often overlooked and commonly undertreated.

- Anxiety.

- Depression.

- Inflammation

- Discoloration

- Skin thickening

- Cellulitis

Secondary lymphedema is a condition characterized by swelling of the soft tissues in which an excessive amount of lymph has accumulated, and is caused by certain malignant diseases such as Hodgkin's disease and Kaposi sarcoma.

Secondary lymphedema also can be caused by several non-malignant diseases, such as lipedema, and can result from the removal of lymph nodes during various cancer surgeries, especially for breast and prostate cancers.

Yellow nail syndrome, also known as "primary lymphedema associated with yellow nails and pleural effusion", is a very rare medical syndrome that includes pleural effusions, lymphedema (due to under development of the lymphatic vessels) and yellow nails. Approximately 40% will also have bronchiectasis. It is also associated with chronic sinusitis and persistent coughing. It usually affects adults.

Goldman states that "numerous inherited or congenital conditions display cutaneous telangiectasia".

These include:

- Naevus flammeus (port-wine stain)

- Klippel-Trenaunay syndrome

- Maffucci's syndrome (multiple enchondromas & hemangiomas)

- Hereditary hemorrhagic telangiectasia (Osler-Weber-Rendu syndrome)

- Ataxia-telangiectasia

- Sturge-Weber syndrome, a nevus formation in the skin supplied by the trigeminal nerve and associated with facial port-wine stains, glaucoma, meningeal angiomas and mental retardation

- Hypotrichosis–lymphedema–telangiectasia syndrome, caused by mutation in transcription factor "SOX18"

Hypotrichosis–lymphedema–telangiectasia syndrome is a congenital syndrome characterized by lymphedema (swelling of tissue due to malformation or malfunction of lymphatics), the presence of telegiectasias (small dilated vessels near the surface of the skin), and hypotrichosis or alopecia (hair loss). Lymphedema usually develops in the lower extremities during puberty. Hair is normal at birth, but usually lost during infancy. Telangiectasias may present on the palms and soles more commonly than on the scalp, legs, and genitalia. The syndrome has been reported in association with both autosomal dominant and autosomal recessive inheritance patterns.

It is associated with a rare mutation of the transcription factor gene "SOX18".

Bullous lymphedema is a skin condition that usually occurs with poorly controlled edema related to heart failure and fluid overload, and compression results in healing.

CPL is a progressive disease, which begins below the fetlock and gradually moves up the leg. All legs are affected, the hindlimbs usually more seriously so. Initial signs include thickening, crusting and folding of the skin. These early signs may be hidden by the long hair (feather) on the horse's lower legs. Affected areas are itchy, causing the horse to stamp its feet and rub its legs, and painful, so that the horse may be reluctant to allow its legs to be touched. As CPL progresses, ulcers develop on the pasterns, and fibrosis leads to hardening of the skin and the development of nodules which may become baseball sized. Secondary infections with microbes or mites commonly cause complications. Infestations with the mange mite "Chorioptes equi" are very itchy, and lead to self-trauma and dermatitis.

The quality of the hoof is often poor; hooves are prone to cracks, splits and the development of thrush and abscesses; horses may develop laminitis. Chestnuts and ergots are often misshapen and irregular.

Telangiectasias, also known as spider veins, are small dilated blood vessels near the surface of the skin or mucous membranes, measuring between 0.5 and 1 millimeter in diameter.

These dilated blood vessels can develop anywhere on the body but are commonly seen on the face around the nose, cheeks, and chin. Dilated blood vessels can also develop on the legs, although when they occur on the legs, they often have underlying venous reflux or "hidden varicose veins" (see "Venous reflux" below). When found on the legs, they are found specifically on the upper thigh, below the knee joint, and around the ankles.

Many patients who suffer with spider veins seek the assistance of physicians who specialize in vein care or peripheral vascular disease. These physicians are called vascular surgeons or phlebologists. More recently, interventional radiologists have started treating venous problems.

Some telangiectasias are due to developmental abnormalities that can closely mimic the behaviour of benign vascular neoplasms. They may be composed of abnormal aggregations of arterioles, capillaries, or venules. Because telangiectasias are vascular lesions, they blanch when tested with diascopy.

Telangiectasia is a component of the CREST variant of scleroderma, also known today as limited scleroderma (CREST is an acronym that stands for calcinosis, Raynaud's phenomenon, esophageal dysmotility, sclerodactyly, and telangiectasia).

Chronic venous insufficiency (CVI) is a medical condition in which blood pools in the veins, straining the walls of the vein. The most common cause of CVI is superficial venous reflux which is a treatable condition. As functional venous valves are required to provide for efficient blood return from the lower extremities, this condition typically affects the legs. If the impaired vein function causes significant symptoms, such as swelling and ulcer formation, it is referred to as chronic venous disease. It is sometimes called "chronic peripheral venous insufficiency" and should not be confused with post-thrombotic syndrome in which the deep veins have been damaged by previous deep vein thrombosis.

Most cases of CVI can be improved with treatments to the superficial venous system or stenting the deep system. Varicose veins for example can now be treated by local anesthetic endovenous surgery.

The prevalence of CVI is far higher in women than in men. The Tampere study, which examined the epidemiology of varicose veins in a large cohort of 3284 men and 3590 women, demonstrated that the prevalence of varicose veins in men and women was 18% and 42%, respectively. The condition has been known since ancient times and Hippocrates used bandaging to treat it.

Chronic progressive lymphedema (CPL) is a disease of some breeds of draft horse, whereby the lower legs becomes progressively more swollen. There is no cure; the aim of treatment is to manage the signs and slow progression of the disease. The cause of CPL is not known, although it is suspected that a genetic disorder of elastin metabolism prevents the lymphatic vessels from functioning properly, leading to edema of the lower limbs. CPL resembles the human disease elephantiasis verrucosa nostra.