XLA is a humoral immunodeficiency, characterized by a defect in B-cell maturation followed by marked reduction in all of the isotypes of serum immunoglobulins as a result of BTK-gene mutation on X-chromosome (
1,
3,
4). Delay in diagnosis of primary immunodeficiencies (PIDs) is usual and these disorders are more common than thought (
4). Since 1952, when Bruton’s disease was first described, the prevalence of infections and frequency of hospital admissions have decreased, because of earlier diagnosis and proper management (
3). Recurrent infections are the main manifestations of PIDs (
3,
5), especially sinopulmonary ones (
6), but other infections such as meningitis, arthritis, osteomyelitis, cellulitis, and gastroenteritis may occasionally occur (
6). In common variable immunodeficiency (CVID) and XLA, compared to the other congenital immunodeficiencies, bone and joint infections are observed more (
6,
7). Nonpathogenic organisms in immunocompetent individuals, like mycoplasma and ureaplasma, are the most common agents causing arthritis in such immunocompromised patients (
6), although
Staphylococcus aureus and streptococcal infections are also commonly observed (
3,
6,
7). Bone and joint abnormalities can occur in patients with PID, with arthritis being the most common joint manifestation. The type of arthritis is usually aseptic oligo/mono arthritis, which can be even the sole presentation (
2,
7,
8). For many years, it was believed that hypogammaglobulinemia and agammaglobulinemia can be associated with symmetric polyarthritis with occasional extra-articular manifestations, resembling RA (
7,
9). A report by Wang XC investigated this issue. In his study, which was conducted on eight patients with suspected XLA, results showed that three of eight had polyarthritis without any evidence of infection (
10). In another study conducted on 281 patients with immunodeficiency, 30 had arthritis as the first presentation, which was more common in individuals with Bruton's disease (22%). Nonspecific arthritis was more common than septic type. Monoarthritis and oligoarthritis were observed in Bruton's disease and CVID, respectively and more commonly arthritis can get septic as a complication of an underlying arthritis due to delayed diagnosis (
9). In conclusion, patients with recurrent arthritis or resistant ones should be assessed for immunodeficiency disorders, especially when other infectious states accompanying during the course of the disease; therefore, awareness of physicians concerning this issue would certainly prevent serious and life-threatening complications in this group of patients.