In terms of management for complement deficiency, immunosuppressive therapy should be used depending on the disease presented. A C1-INH concentrate can be used for angio-oedema (C1-INH deficiency).

Pneumococcus and haemophilus infections prevention can be taken via immunization for those with complement deficiency. Epsilon-aminocaproic acid could be used to treat hereditary C1-INH deficiency, though the possible side effect of intravascular thrombosis should be weighed.

There is a historical popularity in using intravenous immunoglobulin (IVIG) to treat SIGAD, but the consensus is that there is no evidence that IVIG treats this condition. In cases where a patient presents SIGAD and another condition which is treatable with IVIG, then a physician may treat the other condition with IVIG. The use of IVIG to treat SIGAD without first demonstrating an impairment of specific antibody formation is extremely controversial.

The treatment consists of identification of comorbid conditions, preventive measures to reduce the risk of infection, and prompt and effective treatment of infections. Infections in an IgA-deficient person are treated as usual (i.e., with antibiotics). There is no treatment for the underlying disorder.

The treatment of primary immunodeficiencies depends foremost on the nature of the abnormality. Somatic treatment of primarily genetic defects is in its infancy. Most treatment is therefore passive and palliative, and falls into two modalities: managing infections and boosting the immune system.

Reduction of exposure to pathogens may be recommended, and in many situations prophylactic antibiotics or antivirals may be advised.

In the case of humoral immune deficiency, immunoglobulin replacement therapy in the form of intravenous immunoglobulin (IVIG) or subcutaneous immunoglobulin (SCIG) may be available.

In cases of autoimmune disorders, immunosuppression therapies like corticosteroids may be prescribed.

C2 deficiency has a prevalence of 1 in about 20,000 people in Western countries.

Bone marrow transplant may be possible for Severe Combined Immune Deficiency and other severe immunodeficiences.

Virus-specific T-Lymphocytes (VST) therapy is used for patients who have received hematopoietic stem cell transplantation that has proven to be unsuccessful. It is a treatment that has been effective in preventing and treating viral infections after HSCT. VST therapy uses active donor T-cells that are isolated from alloreactive T-cells which have proven immunity against one or more viruses. Such donor T-cells often cause acute graft-versus-host disease (GVHD), a subject of ongoing investigation. VSTs have been produced primarily by ex-vivo cultures and by the expansion of T-lymphocytes after stimulation with viral antigens. This is carried out by using donor-derived antigen-presenting cells. These new methods have reduced culture time to 10–12 days by using specific cytokines from adult donors or virus-naive cord blood. This treatment is far quicker and with a substantially higher success rate than the 3–6 months it takes to carry out HSCT on a patient diagnosed with a primary immunodeficiency. T-lymphocyte therapies are still in the experimental stage; few are even in clinical trials, none have been FDA approved, and availability in clinical practice may be years or even a decade or more away.

Treatment for "B cell deficiency"(humoral immune deficiency) depends on the cause, however generally the following applies:

- Treatment of infection(antibiotics)

- Surveillance for malignancies

- Immunoglobulin replacement therapy

Primary prophylaxis with low-molecular weight heparin, heparin, or warfarin is often considered in known familial cases. Anticoagulant prophylaxis is given to all who develop a venous clot regardless of underlying cause.

Studies have demonstrated an increased risk of recurrent venous thromboembolic events in patients with protein C deficiency. Therefore, long-term anticoagulation therapy with warfarin may be considered in these patients.

Homozygous protein C defect constitutes a potentially life-threatening disease, and warrants the use of supplemental protein C concentrates.

Liver transplant may be considered curative for homozygous protein C deficiency.

In congenital FXII deficiency treatment is not necessary. In acquired FXII deficiency the underlying problem needs to be addressed.

Heterozygous protein C deficiency occurs in 0.14–0.50% of the general population. Based on an estimated carrier rate of 0.2%, a homozygous or compound heterozygous protein C deficiency incidence of 1 per 4 million births could be predicted, although far fewer living patients have been identified. This low prevalence of patients with severe genetic protein C deficiency may be explained by excessive fetal demise, early postnatal deaths before diagnosis, heterogeneity in the cause of low concentrations of protein C among healthy individuals and under-reporting.

The incidence of protein C deficiency in individuals who present with clinical symptoms has been reported to be estimated at 1 in 20,000.

Treatment of THB deficiencies consists of THB supplementation (2–20 mg/kg per day) or diet to control blood phenylalanine concentration and replacement therapy with neurotransmitters precursors (L-DOPA and 5-HTP) and supplements of folinic acid in DHPR deficiency.

Tetrahydrobiopterin is available as a tablet for oral administration in the form of "tetrahydrobiopterin dihydrochloride" (BH4*2HCL). BH4*2HCL is FDA approved under the trade name Kuvan. The typical cost of treating a patient with Kuvan is $100,000 per year. BioMarin holds the patent for Kuvan until at least 2024, but Par Pharmaceutical has a right to produce a generic version by 2020. BH4*2HCL is indicated at least in tetrahydrobiopterin deficiency caused by GTPCH deficiency or PTPS deficiency.

The treatment is some form of Vitamin E supplementation.

Aggressive vitamin E replacement therapy has been shown to either prevent, halt or improve visual abnormalities.

Once a diagnosis is made, the treatment is based on an individual’s clinical condition. Based on the apparent activation of the mTOR pathway, Lucas and colleagues treated patients with rapamycin, an mTOR inhibitor. This effectively reduced hepatosplenomegaly and lymphadenopathy, most likely by restoring the normal balance of naïve, effector, and memory cells in the patients’ immune system. More research is needed to determine the most effective timing and dosage of this medication and to investigate other treatment options. Investigators at the National Institute of Allergy and Infectious Diseases at the US National Institutes of Health currently have clinical protocols to study new approaches to the diagnosis and treatment of this disorder.

There are several treatments available for bleeding due to factor X deficiency, however a specifi FX concentrate is not available (2009).

1. Prothrombin complex concentrate (PCC) supplies FX with a risk of thrombosis.

2. Fresh frozen plasma (FFP): This is relatively inexpensive and readily available. While effective this treatment carries a risk of blood-borne viruses and fluid overload.

3. If vitamin K levels are low, vitamin K can be supplied orally or parenterally.

Treatment of FX deficiency in amyloidosis may be more complex and involve surgery (splenectomy) and chemotherapy.

PNP-deficiency is extremely rare. Only 33 patients with the disorder in the United States have been documented. In the United Kingdom only one child has been diagnosed with this disorder.

Medications can interfere with folate utilization, including:

- anticonvulsant medications (such as phenytoin, primidone, carbamazepine or valproate )

- metformin (sometimes prescribed to control blood sugar in type 2 diabetes)

- methotrexate, an anti-cancer drug also used to control inflammation associated with Crohn's disease, ulcerative colitis and rheumatoid arthritis.

- sulfasalazine (used to control inflammation associated with Crohn's disease, ulcerative colitis and rheumatoid arthritis)

- triamterene (a diuretic)

- birth control pills

When methotrexate is prescribed, folic acid supplements are sometimes given with the methotrexate. The therapeutic effects of methotrexate are due to its inhibition of dihydrofolate reductase and thereby reduce the rate "de novo" purine and pyrimidine synthesis and cell division. Methotrexate inhibits cell division and is particularly toxic to fast dividing cells, such as rapidly dividing cancer cells and the progenitor cells of the immune system. Folate supplementation is beneficial in patients being treated with long-term, low-dose methotrexate for inflammatory conditions, such as rheumatoid arthritis (RA) or psoriasis, to avoid macrocytic anemia caused by folate deficiency. Folate is often also supplemented before some high dose chemotherapy treatments in an effort to protect healthy tissue. However, it may be counterproductive to take a folic acid supplement with methotrexate in cancer treatment.

The life expectancy of patients with homocystinuria is reduced only if untreated. It is known that before the age of 30, almost one quarter of patients die as a result of thrombotic complications (e.g., heart attack).

Low-protein food is recommended for this disorder, which requires food products low in particular types of amino acids (e.g., methionine).

Current research suggests that nearly 8% of the population has at least partial DPD deficiency. A diagnostics determination test for DPD deficiency is available and it is expected that with a potential 500,000 people in North America using 5-FU this form of testing will increase. The whole genetic events affecting the DPYD gene and possibly impacting on its function are far from being elucidated, and epigenetic regulations could probably play a major role in DPD deficiency. It seems that the actual incidence of DPD deficiency remains to be understood because it could depend on the very technique used to detect it. Screening for genetic polymorphisms affecting the "DPYD" gene usually identify less than 5% of patients bearing critical mutations, whereas functional studies suggest that up to 20% of patients could actually show various levels of DPD deficiency.

Women could be more at risk than men. It is more common among African-Americans than it is among Caucasians.

Factor X deficiency (X as Roman numeral ten) is a bleeding disorder characterized by a lack in the production of factor X (FX), an enzyme protein that causes blood to clot in the coagulation cascade. Produced in the liver FX when activated cleaves prothrombin to generate thrombin in the intrinsic pathway of coagulation. This process is vitamin K dependent and enhanced by activated factor V.

The condition may be inherited or, more commonly, acquired.

This condition is very rare; approximately 600 cases have been reported worldwide. In most parts of the world, only 1% to 2% of all infants with high phenylalanine levels have this disorder. In Taiwan, about 30% of newborns with elevated levels of phenylalanine have a deficiency of THB.

Factor XII deficiency (also Hageman factor deficiency) is a deficiency in the production of factor XII (FXII), a plasma glycoprotein and clotting factor that participates in the coagulation cascade and activates factor XI. FXII appears to be not essential for blood clotting, as individuals with this condition are usually asymptomatic and form blood clots in vivo. FXII deficiency tends to be identified during presurgical laboratory screening for bleeding disorders.

The condition can be inherited or acquired.

Folate is found in leafy green vegetables. Multi-vitamins also tend to include Folate as well as many other B vitamins. B vitamins, such as Folate, are water-soluble and excess is excreted in the urine.

When cooking, use of steaming, a food steamer, or a microwave oven can help keep more folate content in the cooked foods, thus helping to prevent folate deficiency.

Folate deficiency during human pregnancy has been associated with an increased risk of infant neural tube defects. Such deficiency during the first four weeks of gestation can result in structural and developmental problems. NIH guidelines recommend oral B vitamin supplements to decrease these risks near the time of conception and during the first month of pregnancy.

In April 2009, hydroxypropyl-beta-cyclodextrin (HPbCD) was approved under compassionate use by the U.S. Food and Drug Administration (FDA) to treat Addison and Cassidy Hempel, identical twin girls suffering from Niemann–Pick type C disease. Medi-ports, similar to ports used to administer chemotherapy drugs, were surgically placed into the twins' chest walls and allow doctors to directly infuse HPbCD into their bloodstreams. Treatment with cyclodextrin has been shown to delay clinical disease onset, reduced intraneuronal storage and secondary markers of neurodegeneration, and significantly increased lifespan in both the Niemann–Pick type C mice and feline models. This is the second time in the United States that cyclodextrin alone has been administered in an attempt treat a fatal pediatric disease. In 1987, HPbCD was used in a medical case involving a boy suffering from severe hypervitaminosis A.

On May 17, 2010, the FDA granted Hydroxypropyl-beta-cyclodextrin orphan drug status and designated HPbCD cyclodextrin as a potential treatment for Niemann–Pick type C disease. On July 14, 2010, Dr. Caroline Hastings of UCSF Benioff Children's Hospital Oakland filed additional applications with the FDA requesting approval to deliver HPbCD directly into the central nervous systems of the twins in an attempt to help HPbCD cross the blood–brain barrier. The request was approved by the FDA on September 23, 2010, and bi-monthly intrathecal injections of HPbCD into the spine were administered starting in October 2010.

On December 25, 2010, the FDA granted approval for HPbCD to be delivered via IV to an additional patient, Peyton Hadley, aged 13, under an IND through Rogue Regional Medical Center in Medford, Oregon. Soon after in March 2011, approval was sought for similar treatment of his sibling, Kayla, age 11, and infusions of HPbCD began shortly after. Both have since begun intrathecal treatments beginning in January 2012.

In April 2011, the National Institutes of Health (NIH), in collaboration with the Therapeutics for Rare and Neglected Diseases Program (TRND), announced they were developing a clinical trial utilizing cyclodextrin for Niemann–Pick type C patients.

On September 20, 2011, the European Medicines Agency (EMA) granted HPbCD orphan drug status and designated the compound as a potential treatment for Niemann–Pick type C disease.

On December 31, 2011, the FDA granted approval for IV HPbCD infusions for a fifth child in the United States, Chase DiGiovanni, under a compassionate use protocol. The child was 29 months old at the time of his first intravenous infusion, which was started in January 2012.

Due to unprecedented collaboration between individual physicians and parents of children afflicted with NPC, approximately 15 patients worldwide have received HPbCD cyclodextrin therapy under compassionate use treatment protocols. Treatment involves a combination of intravenous therapy (IV), intrathecal therapy (IT) and intracerebroventricular (ICV) cyclodextrin therapy.

On January 23, 2013, a formal clinical trial to evaluate HPβCD cyclodextrin therapy as a treatment for Niemann–Pick disease, type C was announced by scientists from the NIH's National Center for Advancing Translational Sciences (NCATS) and the Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD). A Phase I clinical trial is currently being conducted at the NIH Clinical Center.

Raw eggs should be avoided in those with biotin deficiency, because egg whites contain high levels of the anti-nutrient avidin. The name avidin literally means that this protein has an "avidity" (Latin: "to eagerly long for") for biotin. Avidin binds irreversibly to biotin and this compound is then excreted in the urine.