Pathological Illustration: Alopecia Areata

For a render monkey like me, Shelley’s pathology was probably the best palce to get all the drawing out of your system since Dave’s carbon dust assignments. Shelley kick-started the project with the Tissue Landscape Exercise, inspired by the 1966 Fantastic Voyage. Sidenote: on our exchange trip to University Illinois Chicago (shout out to BVis), I got to snap a picture of the original concept art by Frank Amitage, who worked on the movie.

The exercise prompts you to make the tissue space larger-than-life and explore 1) perspective (one point? two point? atmospheric?), and 2) level of complexity (cellular scale? micro-anatomy? gross anatomy?). I already knew that I wanted to pick a dermatology topic. I’ve noticed that the intricacy of the dermal vasculature is hugely under-appreciated in illustrations, so I made that as my landscape’s focus:

This is a rough, rough sketch, but it served its purpose of bringing another interesting topic to my attention: Hair. While looking for skin tissue references in Radivoj V. Krstic’s Microscopic Anatomy, I came across this:

How fun would drawing those layers of cells  be! Can hair be a good pathology topic? What about the pathology of hair loss! Male pattern hair loss is relatively well-understood. What about a female hairloss disorder? What are some of the common causes for female hair loss? A quick search in the libray catelogue brought Alopecia Areata (AA) to my attention (although it may affect either gender), and I’m immediately fascinated by it. Unlike male-or-female pattern of baldness which are hormonal, AA is an autoimmune disorder. Lots of questions yet to be resolved. Lots of new treatment oppotunity underway.

Sounds like a perfect patho topic!

The next stage of planning is drawing tissue cubes, where you focus on depicting the actual disease process:

Did I say drawing all those cellular layers were fun? Well I take that back:

The exercises are here to help you troubleshoot what’s to come. The tissue cubes made me realize just how challenging communicating alopecia areata really is. You hair is alive, and has a life cycle. Alopecia areata happens because your immune cell targets specific cell types at specific stages of that cycle. Therefore, you need to include the full hair anatomy, including the vasculature to orientate your readers about where the immune cells came from. The target cell layer, and the other layers to help define its relative position, must be kept. Because the development of the disease parallels the development of hair’s natural physiology, the same visual treatment of the micro-hair-anatomy should therefore be present in the depiction of all stages.

This Nature Reviews Disease Primers article as well as the review paper that goes with it are one of my primary source. I particularly liked how they broke down the affected hair layers, which prompted me layout the story as follows:

However, when I presented this version to the class for critique, I realized that I have sacrificed scope to clarity. The people reading it had a hard time putting three steps together as a cycle. So in the next version of the layout, I included more steps, and amplified the human factor:

The feedback on the cycle improved slightly, however people still had a hard time connecting the stages of the cycles. I later realized the disconnect happened because first, people had no idea how a normal hair cycle should look, which made understanding what a “disrupted” cycle is difficult. Also, since the call-outs and icons featured a single hair follicle on different planes, the relative difference of each growth stage became less clear. Think about it, as the hair follicle grows down to reach the dermal papilla, the hair shaft grows up from the dermal papilla to reach the skin surface. This two directional change makes setting up a consistent frame of reference especially important. The solution? Compare and contrast normal and alopecia hair cycles. Also, put everything side by side to compare the relative positions of the hair follicle and the hair shaft among all stages.

Which after a series of rendering, became this at the time of winter critique. Since I had a difficult time drawing hand twirling hair, I gave my med-legal partner C (who’s still mega-gorgeous without hair anyways) alopecia:

I received three major critiques: one, even though the attempt of showing the hair cell layers was there, the payoff was negligible (many still can’t explain what a hair follicle is after reading). Two, the render has too many inconsistencies (the molecules especially). The colours were also salient at all the wrong places (why do you need to highlight the veins?). Three, the molecular insights was confusing since there is no apparent reading orde.

Fixing trhe first critique requires redrawing the entire tissue cube, which I think was more than worth it. Instead of the veins, the targeted cell layer became the most salient, while the relative scale difference between the hair and cells were also more clear:

New tissue cube sketches:

AI paths prepared for photoshop painting, fat and cell layers filled with a voronoid pattern:

Final tissue cube render closeup:

In this iteration, I clarified the positioning of each molecular player involved also. The correct molecule and their positioning were imported to the scene using ePMV:

Using this as a reference, I traced over the molecules and rendered them in photoshop:

Since I haven’t encountered any illustrations that depict alopecia areara during my research, this is probably the first visualization that explains the disease at the organismal, tissue, and molecular level all at the same time. Considering all the storytelling challenges this topic presents, I think I’ve reached the stage where I lay my stylus rest until more research comes out. As always, BMC projects are not about the outcome, but the process. Unlike a first year project where every iteration is an opportunity to learn something new, each iteration for patho was more of a guide to the next stage of project development. Given the semester’s timeline, this is was a big project to complete –– where you put all that sweet Infovis knowledge and digital painting skills to the test and truly start to think like a traditional medical illustrator and art director.