This narrative review explores the current landscape of blood biomarkers in Frontotemporal dementia (FTD). Neurofilament light chain (NfL) may be useful in the differentiation of behavioral variant FTD from primary psychiatric disorders (PPDs) or dementia with Lewy bodies (DLB). In prodromal FTD and presymptomatic mutation carriers (GRN, MAPT, C9orf72), elevated NfL may herald pheno-conversion to full-blown dementia. Baseline NfL correlates with steeper neuroanatomical changes and cognitive, behavioral and functional decline, making NfL promising in monitoring disease progression. Phosphorylated neurofilament heavy chain (pNfH) levels have a potential limited role in the demarcation of the conversion stage to full-blown FTD. Combined NfL and pNfH measurements may allow a wider stage stratification. Total tau levels lack applicability in the framework of FTD. p-tau, on the other hand, is of potential value in the discrimination of FTD from Alzheimer’s dementia. Progranulin concentrations could serve the identification of GRN mutation carriers. Glial fibrillary acidic protein (GFAP) may assist in the differentiation of PPDs from behavioral variant FTD and the detection of GRN mutation carriers (additional research is warranted). Finally, TAR DNA-binding protein-43 (TDP-43) appears to be a promising diagnostic biomarker for FTD. Its potential in distinguishing TDP-43 pathology from other FTD-related pathologies requires further research.

Serum sickness-like reaction (SSLR) is a rare immune-mediated condition that typically affects the skin and joints after exposure to certain drugs, infections, or vaccines. Although it shares clinical similarities with serum sickness (SS), SSLR differs in its underlying mechanisms, histopathology, and causes. Despite its generally benign and self-limiting nature, SSLR is frequently misdiagnosed and may lead to unnecessary hospitalization. This narrative review summarizes current knowledge on epidemiology, pathophysiology, clinical features, diagnosis, treatment, and long-term considerations related to SSLR. The condition is most often associated with antibiotics, monoclonal antibodies, and vaccines, particularly in pediatric populations. Its pathogenesis remains incompletely understood, but proposed mechanisms include immune complex formation, altered drug metabolism, lymphocyte toxicity, and the development of anti-drug antibodies. Diagnosis is primarily clinical, although novel diagnostic tools are emerging. Management involves discontinuation of the offending agent and supportive care, such as antihistamines or nonsteroidal anti-inflammatory drugs (NSAIDs) in mild cases, and corticosteroids in more severe cases. Long-term management, especially in cases requiring potential re-exposure to the causative agent, remains challenging. Skin testing and graded oral challenges appear promising within a structured clinical framework. Increased awareness of SSLR is essential for timely recognition and appropriate care, and further research is needed to elucidate its mechanisms and inform evidence-based management strategies.