Discussion of case
The middle-aged female, presented with symmetric inflammatory arthritis, enthesitis, and backache from the past two years, and the symptoms worsened over past year. Her history revealed an episode of urinary tract infection around three months before. The patient earlier had dandruff with flakes, which improved with cream. Tests for RF and ANA were found to be negative. X-ray of hands indicated juxta-articular osteoporosis involving DIP, PIP, and wrist. The possibility of having seronegative spondyloarthropathy (SpA), especially psoriatic/reactive or ankylosing spondylitis should be considered. Other possibilities are rheumatoid arthritis and connective tissue disease. The patient's RF and ANA were negative. A negative anti-CCP test can confirm the possibility of seronegative SpA. X-ray evaluation of the pelvis suggested no evidence of sacroiliitis. The patient had enthesitis which was one of the predominant complaints. The patient fulfilled the following ASAS criteria for SpA.
ASAS classification criteria for axial and peripheral spondyloarthritis1
Fig 1 (A) ASAS classification criteria for axial spondyloarthritis.
Fig 2 (B) ASAS classification criteria for peripheral spondyloarthritis.
*Sacroiliitis on imaging refers to definite radiographic sacroiliitis according to the modified New York criteria or active sacroiliitis on MRI according to the ASAS definition. **Peripheral arthritis: usually predominantly lower limbs and/ or asymmetric arthritis; enthesitis: clinically assessed; dactylitis: clinically assessed. SpA: spondyloarthritis.
The patient had enthesitis and which is the primary clinical feature of spondyloarthritis. She had inflammatory backache and a history of dandruff. The examination did not reveal any skin or scalp lesions. The radiological finding and involvement of DIP suggest possible psoriasis. In addition, the patient had a history of dandruff. The occurrence of dandruff can be due to different causes (Table 4). They commonly include fungal or parasitic infections, inflammatory conditions like psoriasis, and atopic dermatitis.2
Table 4: Comparison of characteristic features of different scalp disorders
| |
Mycotic |
Parasitic pediculosis capitis |
Inflammatory psoriasis |
| Dandruff |
Seborrheic dermatitis |
Tinea capitis |
| Age |
After puberty |
Infancy (cradle cap)
After puberty |
Children, occasionally adults (more common post-menopausal women) |
School children |
Any |
| Fluorescence (wood's lamp) |
N/A |
N/A |
Occasionally (M. Canis, M. adouinni, M. distortum, M. ferrugineum all fluorescence) |
Yes (nits) |
No |
| Pruritus |
Varies |
Mild |
Occasionally |
Severe |
Mild |
| Scaling |
Fine
White or gray |
Large, greasy yellow |
Variable (mild to dense) |
No (nits mat resemble scales) |
Well-demarcated
Silver- gray |
| Inflammation |
No |
Yes |
May occur |
Only with a superinfection |
yes |
| Alopecia |
No |
No |
Yes |
No |
Occasionally |
| Adenopathy |
No |
No |
Cervical and post-auricular |
Only with superinfection usually occipital |
Generally no |
| History |
Hair washing habits |
Recurrence |
Exposure to infected individuals and animals |
Exposure |
Family history
Recalcitrant to treatment |
| Other |
Responds well to over-the-counter shampoo |
Post-auricular region Immunocompromise Neurologic disease |
Affects all races, more common in children of African and Hispanic descent |
More common in Caucasians |
Nail pitting/ onycholysis
Non–scalp lesions
|
However, the dermatologist, whom the patient had consulted before had made a possible diagnosis of psoriasis based on his finding at that time. Though the patient did not have any positive family history of skin disease or nail changes., The patient’s X-ray indicated DIP involvement suggestive of PsA. The classification criteria for psoriatic arthritis (CASPAR) are presented in table 5.
Table 5: The classification criteria for psoriatic arthritis (CASPAR)
| The CASPAR criteria have a specificity of 98.7% and a sensitivity of 91.4%.
Current psoriasis is assigned a score of 2; all other features are assigned a score of 1. To meet the CASPAR (Classification criteria for Psoriatic Arthritis) criteria, a patient must have the inflammatory articular disease (joint, spine, or entheseal) with ≥3 points from the following 5 categories:
1. Evidence of current psoriasis, a personal history of psoriasis, or a family history of psoriasis.
Current psoriasis is defined as psoriatic skin or scalp disease present today as judged by a rheumatologist or dermatologist. †
A personal history of psoriasis is defined as a history of psoriasis that may be obtained from a patient, family physician, dermatologist, rheumatologist, or another qualified health care provider.
A family history of psoriasis is defined as a history of psoriasis in a first- or second-degree relative according to the patient report.
2. Typical psoriatic nail dystrophy including onycholysis, pitting, and hyperkeratosis observed on the current physical examination.
3. A negative test result for the presence of rheumatoid factor by any method except latex but preferably by enzyme-linked immunosorbent assay or nephelometry, according to the local laboratory reference range.
4. Either current dactylitis, defined as swelling of an entire digit, or a history of dactylitis recorded by a rheumatologist.
5. Radiographic evidence of juxta-articular new bone formation, appearing as ill-defined ossification near joint margins (but excluding osteophyte formation) on plain radiographs of the hand or foot |
The patient's history of scalp psoriasis and radiological features was not sufficient to substantiate the diagnosis of psoriatic arthritis as per CASPAR criteria. However, based on the opinion of the dermatologist, the final diagnosis was concluded as psoriatic arthritis.
In the follow-up patient, did develop the skin lesions of psoriasis after 5 months in follow-up. The patient was managed with methotrexate and his symptoms are under control
Final Diagnosis
Psoriatic arthritis
Learning Points
- Psoriatic arthritis should be suspected in the absence of visible skin rashes at presentation
- Careful history of psoriasis and radiographic changes of hands or other joints can suggest the diagnosis.
References
- Banegas Illescas ME, López Menéndez C, Rozas Rodríguez ML, Fernández Quintero RM. [New ASAS criteria for the diagnosis of spondyloarthritis: diagnosing sacroiliitis by magnetic resonance imaging]. Radiologia. 2014;56(1):7-15
- Ramon Grimalt. A Practical Guide to Scalp Disorders. Journal of Investigative Dermatology Symposium Proceedings.2007; 12: 10-14.
