Abstract
BACKGROUND: Transepidermal clearance of altered collagen and excessive excretion of keratin are characteristics of a rare cutaneous disorder known as reactive perforating collagenosis (RPC). There are different forms of RPC; however, the acquired form is the most prevalent and inherited. Reactive perforating collagenosis is rarely described in autoimmune rheumatic diseases; instead, it is typically linked to systemic conditions such as renal failure or hepatic disease. METHODS: A 31-year-old Saudi female patient who was initially diagnosed with undifferentiated connective tissue disease. She developed RPC with a severe diffuse itchy skin rash with numerous papules and nodules with central hyperkeratotic plugs over the lower limb, upper limb, and face. RESULTS: The patient tested positive for antinuclear antibody; however, a year later, patient developed Raynaud's phenomenon, oral and nasal ulcers, malar rash, fatigue, and lupus rash around her eyes, and systemic lupus erythematosus was diagnosed clinically. The patient was treated for reactive perforating collagenosis with systemic antihistamines (diphenhydramine 50 mg orally twice daily), topical steroid cream (betamethasone dipropionate cream), and oral isotretinoin (20 mg daily). The patient was advised to undergo phototherapy. A year later, she presented with symptoms of systemic lupus erythematosus and started taking oral hydroxychloroquine 200 mg twice daily for systemic lupus erythematosus. The patient is listed on follow-up. CONCLUSION: Variable skin rash can mimic systemic lupus erythematosus and vasculitis. Therefore, reactive perforating collagenosis is a skin condition that requires high clinical suspension for diagnosis, and it might be challenging to determine whether it is an association or a complication. Furthermore, the timing of the skin biopsy may be crucial for the diagnosis of reactive perforating collagenosis.