TADA in practice — worked examples

The best way to internalise TADA is to see it applied. Here are five scenarios that demonstrate the algorithm in action, including cases where the safety rules come into play.

Example 1 — Classic seborrhoeic keratosis

What you see: Stuck-on appearance, multiple milia-like cysts, comedo-like openings, sharp borders, uniform brown colour.

Step 1: Does the pattern match one of the three benign lesions? Yes — this is an unequivocal seborrhoeic keratosis. The classic triad is present, the appearance is stuck-on, and there are no features that don't fit.

Outcome: Reassurance is appropriate. Document the finding. No escalation needed.

This is TADA at its most efficient — one step, one clear answer.

Example 2 — Symmetric brown naevus

What you see: Flat brown lesion, regular pigment network fading at edges, symmetric structure, two shades of brown, no history of change.

Step 1: Clear benign pattern? No — it doesn't match seb K, angioma, or dermatofibroma. It's melanocytic.

Step 2: Organised or disorganised? Organised — symmetric, uniform network, orderly colour distribution, gradual transitions at the edge.

Outcome: Consider routine monitoring. Safety-netting advice given. The patient knows to return if the lesion changes.

Most benign naevi will follow this path — not cleared at Step 1, but clearly organised at Step 2.

Example 3 — Asymmetric pigmented lesion

What you see: Irregular borders, asymmetric structure, three colours (brown, dark brown, grey), variable network thickness across the lesion.

Step 1: Clear benign pattern? No.

Step 2: Organised or disorganised? Disorganised — asymmetric structure, multiple colours, irregular network distribution.

Step 3: High-risk features? Yes — atypical network is present (irregular line thickness, variable holes) and blue-grey colour is present.

Outcome: Further evaluation is warranted through your local referral pathway.

Two high-risk features were identified, but remember — even one would have been enough.

Example 4 — Pink nodule, no pigment

What you see: Raised pink lesion, no pigment network visible, dotted vessels across the surface, patient reports it has been growing over recent weeks.

Step 1: Clear benign pattern? No.

Step 2: Organised or disorganised? Difficult to assess — there's no pigmented structure to evaluate. The lesion is amelanotic.

Safety rule triggered: Prediction Without Pigment — this is a changing, growing amelanotic lesion with vessels. History of growth overrides the absence of typical pigmented features.

Outcome: Further evaluation is warranted. The safety rule takes precedence when TADA's pigment-based criteria can't be applied.

This is exactly why the safety rules exist — TADA alone would struggle with this lesion.

Example 5 — Blue-black nodule

What you see: Dome-shaped nodule with dark blue-black colour, smooth surface, no other features obviously visible.

Safety rule triggered immediately: Blue-Black Rule — any nodular lesion with blue-black colour warrants urgent evaluation regardless of other features.

Outcome: Urgent further evaluation. The colour pattern is sufficient. You don't need to work through the full TADA sequence.

Sometimes the safety rules override everything. This is one of those times.

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