Table 1 Fortaleza classification
Stages | Symptom | Parasite activity | Time period | |
|---|---|---|---|---|
Penetration | Stage I | Erythema | Penetration | 3–7 h |
Beginning hypertrophy | Stage II | Pruritus, pain, erythema around central dark dot | Beginning hypertrophy | Days 1–2 after penetration, lasting 2–3 days |
White halo | Stage IIIa | White halo surrounding the black dot, faecal coils, egg expulsion | Hypertrophy into a sphere | Days 2–3 after penetration, lasting 3–4 days |
Stage IIIb | White halo, caldera formation, loss of firmness, faecal coils, egg expulsion | Development of a rim surrounding the rear cone | Days 6–7 after penetration, lasting 2 weeks | |
Involution | Stage IVa | No egg excretion, wrinkled lesion | Shrinking hypertrophy, dying parasite | 3–4 weeks after penetration, lasting 1–2 weeks |
Stage IVb | Necrotic, dissected lesion | Dead parasite | 4–6 weeks after penetration, lasting 1–2 weeks | |
Residuum | Stage V | Circular depression in the stratum corneum | No parasite | 6–7 weeks after penetration for several months or permanent |