Description

Familial chilblain lupus is a rare form of hereditary cutaneous lupus erythematosus associated with chilblains.


 

Genes affected:

(1) TREX1 (exonuclease) at 3p21.31

(2) SAMHD1 (exonuclease), at 20pter-q12

(3) STING (signaling molecule in the cytosolic DNA sensing pathway)

 

Clinical features:

(1) family members are affected (autosomal dominant with TREX1)

(2) exposure to cold temperatures or cold water results in painful bluish-red papules, nodules and/or plaques on exposed skin

(3) arthralgias affecting major joints

(4) no evidence of damage to internal organs

(5) negative for photosensitivity

(6) negative for antibodies to Ro/SSA and/or La/SSB

(7) negative for cold agglutinins

 

A biopsy of a skin lesion resembles cutaneous lupus erythematosus. Direct immunofluorescence shows granular depositis of IgM, IgA and C3.

 

Therapy with a JAK1/2 inhibitor can result in significant improvement.

 


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