Janus kinase (JAK) inhibitors are an immune-modulating group of medications. These medications work by disrupting signaling pathways in immune cells that cause inflammation in conditions such as atopic dermatitis.

This treatment guide explains how JAK inhibitors help manage inflammation in atopic dermatitis, a form of eczema that causes inflammation in the skin, including their effects on immune system activity and skin symptoms.

Several studies have found that JAK inhibitors used to treat atopic dermatitis can help improve skin symptoms linked to the disease by reducing the total area affected and the severity of symptoms. Some JAK inhibitors can also improve itching symptoms.

Some evidence suggests that topical JAK inhibitors, such as ruxolitinib, provide better relief than oral medications, but more head-to-head studies are needed.

There are three JAK inhibitors currently available for the treatment of atopic dermatitis in the United States:

  • abrocitinib (Cibinqo)
  • ruxolitinib (Opzelura)
  • upadacitinib (Rinvoq)

Abrocitinib and upadacitinib are available as once-daily pills. Ruxolitinib is a cream that a person can apply directly to affected areas. Doctors typically reserve abrocitnib and upadacitinib for individuals with moderate to severe symptoms of atopic dermatitis. All three medications are suitable for use in people 12 years or older.

Signaling molecules — known as cytokines — trigger cell activity by binding to receptors on the surface of the cell. JAK proteins are attached to the internal regions of these receptors within the cell. When cytokines bind to the receptor, JAK responds by activating other molecules to trigger a signaling cascade known as the JAK-STAT — signal transducer and activator of transcription — pathway.

JAK inhibitors work inside immune cells by blocking JAK signaling activity. This disrupts the JAK-STAT signaling pathway and helps block the overactivation of immune cells, which can lead to inflammation.

Atopic dermatitis can affect many aspects of a person’s well-being, and people with this condition may be more prone to developing mental health concerns.

A 2021 study found that people with atopic dermatitis treated with a JAK inhibitor reported substantial improvements in multiple aspects related to their mental health, including anxiety, depression, and fatigue.

These results suggest that the symptom relief provided by JAK inhibitors may also provide some psychological relief.

In most cases, side effects with JAK inhibitors are mild and tend to improve over time. Side effects may be more common with oral JAK inhibitors than topical ones since they can reach more areas of the body. The most common side effects are nausea, headaches, upper respiratory infections, and swelling in the nose and throat.

However, some JAK inhibitors can cause severe side effects in rare cases. The Food and Drug Administration (FDA) has added caution to some JAK inhibitors — including upadacitinib — that taking these medications for extended periods may increase the likelihood of developing severe effects. These include blood clots, heart effects, and some types of cancer.