Cutaneous lupus erythematosus in Sarawak, East Malaysia

F. B. B. Yap

 Department of Dermatology, Sarawak General Hospital, Jalan Hospital, 93586 Kuching, Sarawak, Malaysia

Correspondence Address:
F. B. B. Yap
Department of Dermatology, Sarawak General Hospital, Jalan Hospital, 93586 Kuching, Sarawak
Malaysia

Sir,

Cutaneous lupus erythematosus is divided into acute cutaneous lupus erythematosus (ACLE), subacute cutaneous lupus erythematosus (SCLE) and chronic cutaneous lupus erythematosus (CCLE). ACLE has a strong association with systemic lupus erythematosus (SLE), while 50% of SCLE has SLE. A retrospective study was conducted between 2005 and 2007 to determine the clinical and immunological characteristics of patients with cutaneous lupus erythematosus diagnosed both clinically and histopathologically in the skin clinic at Sarawak General Hospital.

In the current study, ACLE constitute erythema, edema and scaling over the malar region and/or photodistributed areas. SCLE manifests as either psoriasiform or annular rashes. CCLE consists of discoid lupus erythematosus (DLE), lupus panniculitis, lupus tumidus, hypertrophic lupus erythematosus or chilblain lupus. The immunological markers for this study consisted of antinuclear antibodies (ANA), anti-double-stranded DNA antibodies (anti-dsDNA) and extractable nuclear antigens antibodies (ENA). The ENA test comprises anti-Ro, anti-La, anti-ribonucleoprotein (anti-rnp), anti-Scl70, anti-Smith and antimitochondrial antibodies (AMA). ANA and anti-dsDNA tests were conducted in the Central Laboratory, Sarawak General Hospital, using an indirect immunofluorescence technique with human epithelial (Hep- 2) cells. The ENA tests were carried out in Institute of Medical Research (IMR), Kuala Lumpur. An ANA titer of 1:80 or more was considered positive. Other tests were qualitative.

One hundred and eighteen patients were seen, of which 47.5% (n = 56) had ACLE, 39.8% (n = 47) had CCLE and 12.7% (n = 15) had SCLE [Table - 1]. This is in contrast with the findings of Ng et al ., in Singapore where 58.4% of their 125 patients had DLE, 17.6% had ACLE and only 6.4% had SCLE, ^[1] A higher proportion of ACLE and SCLE was noted here. It is postulated that most of the patients with mild CCLE might not present to the skin clinic as most parts of Sarawak has poor infrastructure and socioeconomic status, making difficult the accessibility to the skin clinic.

All the ACLE patients had malar rash, with only 35.7% (n = 20) having concomitant photodistributed rash. Eigthy percent of SCLE patients had psoriasiform lesions, whereas the remaining had annular lesions. Drosos in Greece also noted a similar distribution. ^[2] DLE represented 83.3% (n = 39) of CCLE in this study, while the remaining had lupus panniculitis. Other variants of CCLE were not seen. This is not dissimilar to findings in Brazil and Singapore. ^[1],[3]

Concomitant SLE was seen in all patients with ACLE, in 17.9% with SCLE and in 8.9% with CCLE. Ng et al ., noted that 63% of their SCLE patients and 9.6% CCLE patients had concomitant SLE. ^[1] A very low association was noted between SCLE and SLE in the current study.The male to female ratio was 6.4:1 with 13:1 in ACLE, 1:0 in SCLE and 2.9:1 in CCLE. This ratio was similar to those found by others. ^[1],[2]

In this series, positive ANA was noted in 85.7% of ACLE patients, 53.3% of SCLE patients and 44.5% of CCLE patients. Anti-dsDNA was detected in 52% patients with ACLE and 12.8% with CCLE, with none of those with SCLE having dsDNA. In Singapore, ANA was present in the majority of ACLE (85%) and SCLE (88%) patients but only in 25% of DLE patients. ^[1] Malay SLE patients in Kelantan manifested positive dsDNA in 53.7% patients. ^[4] Thus, findings of this study correspond to those of other regional studies.

In this study, anti-Ro and anti-La were detected in only 20% of patients with SCLE. Drosos noted a 70% positive anti-Ro and anti-La in their SCLE series. ^[2] Wang noted that 36% of Malaysian SLE patients had anti-Ro and only 8% had anti-La. ^[5] This rate was far lower than other Oriental patients in Singapore and Hong Kong. This might explain the low anti-Ro and anti-La positivity in this series.

In conclusion, the rate of CCLE in Sarawak is lower than other studies. In Sarawak, SCLE has a lower association with SLE and has a lower rate of positive anti-Ro and anti-La.

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