percipitis

Percipitis is a rare, chronic dermatologic condition first identified in rural Southeast Asian populations in the early 1970s. It is characterized by episodic, pruritic, erythematous plaques that often appear on the extremities and trunk. The lesions typically progress through a papular stage to a vesicular stage before resolving or leaving hyperpigmented macules. Recurrence is common, with flare-ups often triggered by humidity, insect bites, or minor trauma.

The etiology of percipitis remains uncertain. Proposed mechanisms include an exaggerated immune response to an unknown environmental allergen, possibly a fungal spore, or a misdirected autoimmune reaction. Several studies have noted a correlation between the prevalence of the species of the fungus *Trichophyton verrucosum* and the incidence of the disease, suggesting a potential zoonotic link. Genetic predisposition has been suggested by familial clustering but definitive susceptibility loci have not yet been identified.

Diagnosis is primarily clinical, relying on symptom history and the characteristic morphology of the lesions. Dermoscopic examination reveals well-demarcated erythema with surrounding scaling. Where available, skin scrapings may assist in ruling out fungal infection. Routine laboratory tests are generally normal, however, inflammatory markers such as erythrocyte sedimentation rate may be mildly elevated during flare states.

Treatment is supportive and symptomatic. Topical corticosteroids are commonly prescribed to reduce inflammation and itching. Antihistamines are recommended for severe pruritus. In resistant cases, a short course of systemic corticosteroids may be employed, though long‑term use is discouraged due to potential side effects. Phototherapy has shown some benefit, particularly for patients experiencing frequent outbreaks. Regular follow‑up is advised to monitor for potential complications such as secondary bacterial infection or pigmentary changes.

Because the disease lacks curative therapy, patient education focuses on trigger avoidance, hygiene, and early symptomatic management. Ongoing research aims to elucidate the precise pathogenetic mechanisms of percipitis and to develop targeted immunomodulatory therapies.