PPD

PPD is an acronym that can refer to several different terms depending on context. Common uses include postpartum depression, the purified protein derivative tuberculin skin test, and paraphenylenediamine, a chemical used in dyes. Each term represents a distinct concept in medicine, immunology, and chemistry.

Postpartum depression (PPD) is a mood disorder that can develop after childbirth. It is more persistent and severe than the transient baby blues and may involve persistent sadness, anxiety, irritability, sleep and appetite changes, fatigue, and difficulties bonding with the infant. Onset typically occurs within the first year after birth. Risk factors include prior depressive episodes, unusual stress, lack of support, and medical complications. Treatment may involve psychotherapy, antidepressant medication when appropriate, and social or peer support; early recognition improves outcomes and can prevent escalation.

Purified Protein Derivative (PPD) is used in the tuberculin skin test to screen for latent tuberculosis infection. The test involves intradermal injection of tuberculin PPD and reading the resulting induration after 48 to 72 hours. The significance of a positive result depends on risk factors such as age, immune status, and exposure; thresholds vary by guidelines. A positive result indicates TB infection but is not a diagnosis; further evaluation with imaging and clinical assessment is necessary. False positives can occur due to prior vaccination with BCG or exposure to non-tuberculous mycobacteria.

Paraphenylenediamine (PPD) is an organic compound used as a primary hair dye ingredient and in other coloring applications. It can cause allergic contact dermatitis in some people, with reactions ranging from mild dermatitis to more severe eczema. Patch testing can identify sensitivity. Due to allergenicity, many regions regulate concentrations, labeling, and the use of alternatives for sensitive individuals.