Over-the-counter medications are readily available and convenient. However, intake may result in cutaneous adverse reactions such as acute generalized exanthematous pustulosis (AGEP). The need to differentiate the disease to similar pustular diseases such as pustular psoriasis and subcorneal pustular dermatosis is essential, to give way to proper patient management. Its appearance with psoriasis vulgaris is uncommon.

We highlight a 36-year-old Filipino female with a known case of psoriasis vulgaris, undergoing phototherapy with good compliance and response, who took one dose of mefenamic acid due to headache. Three days after, she presented with multiple, pin-point pustules surrounded by multiple, erythematous plaques and desquamative scales over the body, including non-psoriatic areas.

A skin punch biopsy on the left arm revealed that the epidermis shows a subcorneal pustule with spongiosis and focal vacuolar alteration at the base. The dermis showed edema and was infiltrated mainly of lymphohistocytes and eosinophils, consistent with acute generalized exanthematous pustulosis.

Treatment with cyclosporine of 3.0 mkd was given, with topical corticosteroids of clobetasol 0.05% ointment mixed with petroleum jelly. Gradual tapering every two weeks was done, with 90% improvement. Blood pressure monitoring was done while on treatment. No recurrence of pustular lesions seen thereafter.

Apart from NSAIDs, beta-lactams, and beta-blockers are common causes of AGEP. There have been few published case reports about concomitant psoriasis vulgaris and acute generalized exanthematous pustulosis. To ascertain the diagnosis among subcorneal pustular dermatosis, pustular psoriasis, acute generalized exanthematous pustulosis, clinical and histopathologic correlation should be done.