Psoriasis may manifest as severe hyperkeratotic lesions resembling an oyster shell called ostraceous psoriasis. This type of psoriasis is extremely rare and is often associated with psoriatic arthritis. Psoriatic arthritis is a chronic inflammatory disease of the joints presenting with pain, stiffness, swelling, tenderness, and limited movements. This is a case of a 16-year-old Filipino female presenting with pruritic erythematous plaques topped with thick adherent ostraceous scales associated with bilateral knee and elbow pains. Laboratory tests and biopsy were done. Histopathology is consistent with psoriasiform dermatitis and psoriatic arthritis is established through Early Psoriatic Arthritis (EARP) Screening Questionnaire and Classification Criteria for Psoriatic Arthritis (CASPAR). Patient was started on potent topical corticosteroids and Narrow-band Ultraviolet B (NB-UVB) phototherapy with minimal improvement. Hence, Secukinumab was initiated which showed significant improvement on the skin lesions and joint pains 7 days after the first dose of Secukinumab. Ostraceous psoriasis is rarely found in pediatric population. It is commonly associated with psoriatic arthritis that should be screened during routine consult. Its characteristic firmly adherent thick scales are resistant to topical treatments. One of the therapeutic options is Secukinumab, an IL-17A selective inhibitor targeting the release of proinflammatory cytokines, chemokines and mediators of tissue damage. It demonstrates immediate effect, significant and sustained improvement in the skin lesions, minimal adverse reactions, as well as improved quality of life and physical function. It is therefore a preferred treatment for patients with moderate to severe psoriasis and psoriatic arthritis requiring rapid clearance.